Unexpected Error, please contact support SAML authentication

I have Version 1.8.9 docker install with SAML Single Signon with Active Directory ADFS. All of a sudden I am getting error when logging Unexpected Error, please contact support. The only changes that I have made is to renew the certificate.Where are the logs so I can troubleshoot the issue? Please advise.

Thank you.

Update: I was able to resolve my issue. The token certificate on the ADFS server had expired. I exported the current certificate and applied it to the custom-settings.php file and no more error.