Problems setting up SSO in Staging

Summary

We are trying to set up SSO in Staging for UAT. Unfortunately we cannot get past the Error 500

Content

I am reaching out to the group before engaging Support on this issue.

I have set the connection up as instructed in the 15 Steps and Implementation guide Documents, but keep getting the 500 error. I have checked as best as possible all the relevant entries to the form making double and triple sure that the .cer file was in Binary x509 as required.

Are there any obvious problems that I am overlooking? IT on our side have confirmed the settings and are puzzled as to the continued error.