Getting a 401 Unauthorized when using a JWT token b/w two services

Question

I have an identity service that generates a JWT token after login. The token is included in the Authorization header as Bearer to access another service. Identity service endpoint: /api/Auth/login Admin service endpoint: /api/Usermanagement Despite ensuring the token is valid and not expired I receive a 401 Unauthorized response. What could be causing this issue

Sangeetha S · Answer

A 401 Unauthorized error when using a JWT token between two services can arise from several potential issues. Here are some common causes to check: Token Not Being Passed Correctly : Ensure that the Authorization header is correctly formatted as Bearer . Any extra spaces or incorrect formatting could lead to issues. Service Configuration : Verify that the service you're trying to access (User management) is correctly configured to accept and validate the JWT token. This includes checking if the service is set to authenticate against the same identity service. Token Signing and Validation : Make sure that both services are using the same secret key or public/private key pair for signing and validating the JWT. If they differ the token will be considered invalid. Claims and Scopes : Check the claims in the JWT token. The target service may be expecting specific claims (like roles or permissions) that are not present in the token. Ensure the token contains the required scopes for accessing the endpoint. CORS Issues : If you're making requests from a frontend application ensure that the backend service has the correct CORS policy to allow requests from the origin of your application. Token Expiry : Double-check that the token is not expired. While you mentioned it's valid ensure that the expiration time ( exp claim) is indeed in the future. Service Endpoint : Ensure that the endpoint you're trying to access is correctly set up and that the route matches the expected path in the service. Network Issues : Occasionally network configurations (like firewalls or proxies) can interfere with requests. Ensure that nothing is blocking the request.