登录后 Azure AD SSO 重定向
Azure AD SSO Redirection After Login
使用 OAUTH 和 Azure AD 进行身份验证后，我无法正确重定向 dashboard.aspx 页面。当我在 VS 2017 中调试时，我能够使用我的 O365 电子邮件和密码登录，并且重定向工作正常。但是，当我发布到 Web 服务器时却没有。该页面似乎只是坐在那里，什么也没做。我尝试将 Azure 中的重定向 URL 更改为 http://domainame.com/dashboard.aspx 但这不起作用。我还在代码隐藏文件中放置了一个重定向语句。我需要部署此应用程序，这是我需要的最后一部分。这也在使用 OWIN。我使用默认的 ASP.NET 模板启动项目，并选择从工作或学校进行身份验证。
下面是 StartUpAuth.cs 文件。我将实际重定向域更改为 domain.name.com 仅用于发布目的。如果代码格式不正确，我深表歉意。每次我尝试时，无论是否有 4 个缩进，我仍然会被否决。
namespace HealthScripts
{
public partial class Startup
{
private static string clientId = ConfigurationManager.AppSettings["ida:ClientId"];
private static string appKey = ConfigurationManager.AppSettings["ida:ClientSecret"];
private static string aadInstance = ConfigurationManager.AppSettings["ida:AADInstance"];
private static string tenantId = ConfigurationManager.AppSettings["ida:TenantId"];
private static string postLogoutRedirectUri = ConfigurationManager.AppSettings["ida:PostLogoutRedirectUri"];
private string authority = aadInstance + tenantId;
// This is the resource ID of the AAD Graph API. We'll need this to request a token to call the Graph API.
private static string graphResourceId = "https://graph.windows.net";
public void ConfigureAuth(IAppBuilder app)
{
app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);
app.UseCookieAuthentication(new CookieAuthenticationOptions());
app.UseOpenIdConnectAuthentication(
new OpenIdConnectAuthenticationOptions
{
ClientId = clientId,
Authority = authority,
PostLogoutRedirectUri = postLogoutRedirectUri,
//RedirectUri = "https://domain.name.com/HealthScripts-Staging/",
Notifications = new OpenIdConnectAuthenticationNotifications()
{
//
// If there is a code in the OpenID Connect response, redeem it for an access token and refresh token, and store those away.
//
AuthorizationCodeReceived = (context) =>
{
var code = context.Code;
ClientCredential credential = new ClientCredential(clientId, appKey);
string signedInUserID = context.AuthenticationTicket.Identity.FindFirst(ClaimTypes.NameIdentifier).Value;
AuthenticationContext authContext = new AuthenticationContext(authority, new ADALTokenCache(signedInUserID));
AuthenticationResult result = authContext.AcquireTokenByAuthorizationCode(
code, new Uri(HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Path)), credential, graphResourceId);
return Task.FromResult(0);
}
}
}
);
// This makes any middleware defined above this line run before the Authorization rule is applied in web.config
app.UseStageMarker(PipelineStage.Authenticate);
}
}
}
[Win32Exception (0x80004005): The system cannot find the file specified]
[SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 52 - Unable to locate a Local Database Runtime installation. Verify that SQL Server Express is properly installed and that the Local Database Runtime feature is enabled.)]
System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTransientFaultHandling) +1379
System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +452
System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +70
System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +927
System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +109
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +1550
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +117
System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection) +258
System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) +314
System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry) +126
System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry) +255
System.Data.SqlClient.SqlConnection.Open() +128
System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch(TTarget target, Action`2 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed) +101
System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext) +509
System.Data.Entity.SqlServer.<>c__DisplayClass33.<UsingConnection>b__32() +561
System.Data.Entity.SqlServer.<>c__DisplayClass1.<Execute>b__0() +15
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Func`1 operation) +231
System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection sqlConnection, Action`1 act) +911
System.Data.Entity.SqlServer.SqlProviderServices.CreateDatabaseFromScript(Nullable`1 commandTimeout, DbConnection sqlConnection, String createDatabaseScript) +117
System.Data.Entity.SqlServer.SqlProviderServices.DbCreateDatabase(DbConnection connection, Nullable`1 commandTimeout, StoreItemCollection storeItemCollection) +211
System.Data.Entity.Migrations.Utilities.DatabaseCreator.Create(DbConnection connection) +125
System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) +156
System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration) +116
System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func`3 createMigrator, ObjectContext objectContext) +121
System.Data.Entity.Database.Create(DatabaseExistenceState existenceState) +292
System.Data.Entity.CreateDatabaseIfNotExists`1.InitializeDatabase(TContext context) +187
System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) +69
System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() +482
System.Data.Entity.Internal.RetryAction`1.PerformAction(TInput input) +174
System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action`1 action) +269
System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) +38
System.Data.Entity.Internal.Linq.InternalSet`1.Initialize() +77
System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext() +21
System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider() +59
System.Linq.Queryable.FirstOrDefault(IQueryable`1 source, Expression`1 predicate) +61
HealthScripts.Models.ADALTokenCache..ctor(String signedInUserId) in C:\Users\tadams\Desktop\Important Projects\HS-MAIN\HealthScripts\HealthScripts\Models\AdalTokenCache.cs:14
HealthScripts.Startup.<ConfigureAuth>b__7_0(AuthorizationCodeReceivedNotification context) in C:\Users\tadams\Desktop\Important Projects\HS-MAIN\HealthScripts\HealthScripts\App_Start\StartupAuth.cs:54
Microsoft.Owin.Security.OpenIdConnect.<AuthenticateCoreAsync>d__1a.MoveNext() +5389
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
Microsoft.Owin.Security.OpenIdConnect.<AuthenticateCoreAsync>d__1a.MoveNext() +5898
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Security.Infrastructure.<BaseInitializeAsync>d__0.MoveNext() +817
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Security.Infrastructure.<Invoke>d__0.MoveNext() +329
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Security.Infrastructure.<Invoke>d__0.MoveNext() +768
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.<RunApp>d__5.MoveNext() +194
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.<DoFinalWork>d__2.MoveNext() +184
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) +117
System.Web.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +365
System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +195
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +128
如果您的 SSO 在本地有效，则在已发布的版本中将无效，反之亦然。检查以确保在 Azure 门户和代码配置中将回复 URL 设置为已发布的应用程序 URL。
有关参考，请参阅此文档：https://github.com/Azure-Samples/active-directory-dotnet-webapp-openidconnect
"The system cannot find the file specified." 此错误消息表示客户端可以访问服务器，但在目标计算机上没有具有特定管道名称的命名管道侦听器。这也意味着该帐户可以毫无问题地进行文件共享会话。
可能的原因是：
a) 实例名称输入错误或实例名称错误。实例名称不是您要定位的名称。请注意，对于默认实例，您不应使用 MSSQLSERVER 作为实例名称。
b) 目标 SQL 服务器不是 运行
c) 服务器上未启用命名管道。
d) 您正在使用不同的版本并且缺少依赖项。
确保您可以使用 SSMS 手动连接到 SQL 服务器。如果是，则更新应用程序 web.config 内的连接字符串。如果您无法使用 SSMS 连接到 SQL 服务器，那么您需要解决问题：https://social.technet.microsoft.com/wiki/contents/articles/2102.how-to-troubleshoot-connecting-to-the-sql-server-database-engine.aspx
使用 OAUTH 和 Azure AD 进行身份验证后，我无法正确重定向 dashboard.aspx 页面。当我在 VS 2017 中调试时，我能够使用我的 O365 电子邮件和密码登录，并且重定向工作正常。但是，当我发布到 Web 服务器时却没有。该页面似乎只是坐在那里，什么也没做。我尝试将 Azure 中的重定向 URL 更改为 http://domainame.com/dashboard.aspx 但这不起作用。我还在代码隐藏文件中放置了一个重定向语句。我需要部署此应用程序，这是我需要的最后一部分。这也在使用 OWIN。我使用默认的 ASP.NET 模板启动项目，并选择从工作或学校进行身份验证。 下面是 StartUpAuth.cs 文件。我将实际重定向域更改为 domain.name.com 仅用于发布目的。如果代码格式不正确，我深表歉意。每次我尝试时，无论是否有 4 个缩进，我仍然会被否决。
namespace HealthScripts
{
public partial class Startup
{
private static string clientId = ConfigurationManager.AppSettings["ida:ClientId"];
private static string appKey = ConfigurationManager.AppSettings["ida:ClientSecret"];
private static string aadInstance = ConfigurationManager.AppSettings["ida:AADInstance"];
private static string tenantId = ConfigurationManager.AppSettings["ida:TenantId"];
private static string postLogoutRedirectUri = ConfigurationManager.AppSettings["ida:PostLogoutRedirectUri"];
private string authority = aadInstance + tenantId;
// This is the resource ID of the AAD Graph API. We'll need this to request a token to call the Graph API.
private static string graphResourceId = "https://graph.windows.net";
public void ConfigureAuth(IAppBuilder app)
{
app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);
app.UseCookieAuthentication(new CookieAuthenticationOptions());
app.UseOpenIdConnectAuthentication(
new OpenIdConnectAuthenticationOptions
{
ClientId = clientId,
Authority = authority,
PostLogoutRedirectUri = postLogoutRedirectUri,
//RedirectUri = "https://domain.name.com/HealthScripts-Staging/",
Notifications = new OpenIdConnectAuthenticationNotifications()
{
//
// If there is a code in the OpenID Connect response, redeem it for an access token and refresh token, and store those away.
//
AuthorizationCodeReceived = (context) =>
{
var code = context.Code;
ClientCredential credential = new ClientCredential(clientId, appKey);
string signedInUserID = context.AuthenticationTicket.Identity.FindFirst(ClaimTypes.NameIdentifier).Value;
AuthenticationContext authContext = new AuthenticationContext(authority, new ADALTokenCache(signedInUserID));
AuthenticationResult result = authContext.AcquireTokenByAuthorizationCode(
code, new Uri(HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Path)), credential, graphResourceId);
return Task.FromResult(0);
}
}
}
);
// This makes any middleware defined above this line run before the Authorization rule is applied in web.config
app.UseStageMarker(PipelineStage.Authenticate);
}
}
}
[Win32Exception (0x80004005): The system cannot find the file specified]
[SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 52 - Unable to locate a Local Database Runtime installation. Verify that SQL Server Express is properly installed and that the Local Database Runtime feature is enabled.)]
System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTransientFaultHandling) +1379
System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +452
System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +70
System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +927
System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +109
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +1550
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +117
System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection) +258
System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) +314
System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry) +126
System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry) +255
System.Data.SqlClient.SqlConnection.Open() +128
System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch(TTarget target, Action`2 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed) +101
System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext) +509
System.Data.Entity.SqlServer.<>c__DisplayClass33.<UsingConnection>b__32() +561
System.Data.Entity.SqlServer.<>c__DisplayClass1.<Execute>b__0() +15
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Func`1 operation) +231
System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection sqlConnection, Action`1 act) +911
System.Data.Entity.SqlServer.SqlProviderServices.CreateDatabaseFromScript(Nullable`1 commandTimeout, DbConnection sqlConnection, String createDatabaseScript) +117
System.Data.Entity.SqlServer.SqlProviderServices.DbCreateDatabase(DbConnection connection, Nullable`1 commandTimeout, StoreItemCollection storeItemCollection) +211
System.Data.Entity.Migrations.Utilities.DatabaseCreator.Create(DbConnection connection) +125
System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) +156
System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration) +116
System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func`3 createMigrator, ObjectContext objectContext) +121
System.Data.Entity.Database.Create(DatabaseExistenceState existenceState) +292
System.Data.Entity.CreateDatabaseIfNotExists`1.InitializeDatabase(TContext context) +187
System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) +69
System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() +482
System.Data.Entity.Internal.RetryAction`1.PerformAction(TInput input) +174
System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action`1 action) +269
System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) +38
System.Data.Entity.Internal.Linq.InternalSet`1.Initialize() +77
System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext() +21
System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider() +59
System.Linq.Queryable.FirstOrDefault(IQueryable`1 source, Expression`1 predicate) +61
HealthScripts.Models.ADALTokenCache..ctor(String signedInUserId) in C:\Users\tadams\Desktop\Important Projects\HS-MAIN\HealthScripts\HealthScripts\Models\AdalTokenCache.cs:14
HealthScripts.Startup.<ConfigureAuth>b__7_0(AuthorizationCodeReceivedNotification context) in C:\Users\tadams\Desktop\Important Projects\HS-MAIN\HealthScripts\HealthScripts\App_Start\StartupAuth.cs:54
Microsoft.Owin.Security.OpenIdConnect.<AuthenticateCoreAsync>d__1a.MoveNext() +5389
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
Microsoft.Owin.Security.OpenIdConnect.<AuthenticateCoreAsync>d__1a.MoveNext() +5898
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Security.Infrastructure.<BaseInitializeAsync>d__0.MoveNext() +817
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Security.Infrastructure.<Invoke>d__0.MoveNext() +329
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Security.Infrastructure.<Invoke>d__0.MoveNext() +768
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.<RunApp>d__5.MoveNext() +194
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.<DoFinalWork>d__2.MoveNext() +184
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) +117
System.Web.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +365
System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +195
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +128
如果您的 SSO 在本地有效，则在已发布的版本中将无效，反之亦然。检查以确保在 Azure 门户和代码配置中将回复 URL 设置为已发布的应用程序 URL。
有关参考，请参阅此文档：https://github.com/Azure-Samples/active-directory-dotnet-webapp-openidconnect
"The system cannot find the file specified." 此错误消息表示客户端可以访问服务器，但在目标计算机上没有具有特定管道名称的命名管道侦听器。这也意味着该帐户可以毫无问题地进行文件共享会话。
可能的原因是：
a) 实例名称输入错误或实例名称错误。实例名称不是您要定位的名称。请注意，对于默认实例，您不应使用 MSSQLSERVER 作为实例名称。
b) 目标 SQL 服务器不是 运行
c) 服务器上未启用命名管道。
d) 您正在使用不同的版本并且缺少依赖项。
确保您可以使用 SSMS 手动连接到 SQL 服务器。如果是，则更新应用程序 web.config 内的连接字符串。如果您无法使用 SSMS 连接到 SQL 服务器，那么您需要解决问题：https://social.technet.microsoft.com/wiki/contents/articles/2102.how-to-troubleshoot-connecting-to-the-sql-server-database-engine.aspx