This issue can arise from several factors such as token revocation by the user, token expiration time, or token invalidation due to password reset or security events. Here are some possible steps you can take:
- Try and check the token expiration time and refresh tokens before making any Graph API requests. Ensure that the refresh token has not expired.
- You can try to implement a token refresh mechanism that automatically refreshes the access token when it is close to expiration. You can use the
refresh_token
grant type to obtain a new access token. - If the user's password is reset or the user's account is deleted or disabled, the refresh token will become invalid. In this case, you will need to prompt the user to re-authenticate and grant permission again.
You can use the Microsoft Graph API to retrieve the sign-in logs and audit logs. Relevant documentation can be found here Microsoft Graph API sign-in and audit logs