The app that I am developing now connects to Azure services and DefaultCredential were used for that. In Azure the authentication between services works with managed identities and I am satisfied with them, but while the development I've got an error "Azure.RequestFailedException: Server failed to authenticate the request", so I really didn't know what to do. Yesterday it worked, today not.

The full error message is here

Azure.RequestFailedException: Server failed to authenticate the request. Please refer to the information in the www-authenticate header.
RequestId:510b0d64-e003-0076-2fa0-6ace5e000000
Time:2025-12-11T13:19:15.0538855Z
Status: 401 (Server failed to authenticate the request. Please refer to the information in the www-authenticate header.)
ErrorCode: InvalidAuthenticationInfo

I started to check the permissions, remember when I updated my password. But the solution is very banal - I had just to reauthenticate to Visual Studio. The sign in button is in top right corner of the app.