使用不记名令牌的 React API 调用已被 CORS 策略阻止

React API call with bearer token has been blocked by CORS policy

我正在尝试使用不记名令牌进行 API 调用以获取数据。但是有一个错误Access to fetch at 'https://MYAPI..' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the请求的资源。如果不透明响应满足您的需求,请将请求的模式设置为 'no-cors' 以在禁用 CORS 的情况下获取资源。另外,我的令牌为空。我尝试从 localStorage 获取。local storage token example 这是我的令牌。谁能告诉我我的问题在哪里?谢谢

const [user, setUsers] = React.useState([]);
 var token = localStorage.getItem("accessToken");
    React.useEffect(()=>{
   fetch(URLS.GetAllUsers,{
    method: "GET",
        headers: {
          "Content-Type": "application/json",
          Authorization: "Bearer " + token,
      
        }})
    .then(res=> res.json())
    .then((response) => {
  setUsers(response.displayName)
    })
    .catch((error) => console.log(error));
  });

我认为你必须在服务器内部启用 CORS。