We have hosted Deployment Manager in Dev environment itself. Pipelines were all built successfully, and we have been using it for a while already. We started to face the connectivity issue in the pipelines although the following are valid.

1. DMApp Admin & DMRelease Admin - Valid Passwords updated already

2. Auth Profiles are properly updated

3. PreEmptive Authentication enabled in the Auth Profiles

4. Tried Revoking the existing Access Tokens and re-generated the client secrets and updated them but no use still.