After patching, users report that application links now prompt for logon information. What is the most likely cause?

The most likely cause of the application links prompting for logon information after a patch is related to Single Sign-On (SSO) issues. When a system undergoes patching, especially in network and identity management components, it can inadvertently disrupt the configurations that allow SSO to function properly.

SSO enables users to access multiple applications with a single set of credentials, streamlining the authentication process. If the patch altered any settings, interfaces, or underlying protocols used for SSO, users would then be required to log in to each application separately due to the breakdown in the seamless authentication service.

While password expiration, account lockout, and certificate expiration could also lead to authentication issues, they are less likely to be the immediate cause following a patch. Password expiration would typically result in a request for a new password rather than prompting for a logon each time. Account lockouts would indicate a security issue due to failed login attempts, which would not be directly connected to a recent patch. Certificate expiration might lead to authentication failures, but it is generally less common and would typically result in error messages rather than just prompting for credentials. Therefore, SSO issues stand out as the most plausible explanation in this scenario.