Can an HTTP 401 error indicate a server-side problem rather than a client-side (JDBC) misconfiguration?

Yes, absolutely. While often a client-side credential issue, a 401 can stem from server-side problems such as: the database user account being locked or expired; security policies on the database or an intermediary server (like an API gateway) changing, revoking access, or requiring new authentication methods; a misconfigured authentication provider (e.g., LDAP/Active Directory integration issues); or the database itself being unable to validate the credentials provided.