Authentication Failure on Expired Credentials in Linux Mint

Least Privilege Authentication

The goal is to confirm the precise failure mode when a standard, non-root Linux Mint user attempts authentication with credentials flagged as expired by the system.

Constraints and Uncertainty

The exact behavior is dependent on the underlying PAM configuration, not a default Mint feature alone.

Does the authentication process return a generic permission denied error, or a specific credential expiration notification?

What is the expected PAM module interaction for credential expiry on recent Mint versions?