A technician receives a call from Joe, a user, who is unable to log into any of the company's SaaS application. The applications are provided by multiple vendors. Joe reports his credentials were work

An error with the federation service would typically prevent all users from accessing federated applications, or at least affect a broader range of applications in a similar manner, not just Joe.

If Joe's account were locked out, he would be unable to log into any applications, including locally hosted ones, which contradicts the information given.

A security token typically refers to a session token, which has a limited lifespan, but if it expired, Joe would just be prompted to re-authenticate. The issue is about inability to log in, not just re-authenticating, and it's specific to SaaS apps while local apps work.

Joe can log into locally hosted applications with the same credentials but cannot access multiple SaaS applications from different vendors. This suggests an issue with the mechanism used for secure access to external cloud services, rather than an internal credential problem. Many companies use personal certificates for secure single sign-on (SSO) or multi-factor authentication to SaaS applications, especially when dealing with multiple vendors. If Joe's personal certificate has expired, it would prevent him from authenticating to these external SaaS services while not affecting his ability to log into local applications using traditional username/password authentication.