ABannister,   I beleieve the issue you're seeing is due to the upgrade itself, what I would recommend is to uninstall SGC and then reinstall directly with the version you had upgraded to.   Let me know if this helps.    
After upgrading SupportAssist to SCG.  Registration has started on first open, connect and authentication is successful but I cannot complete the registration due to a fail at Stage 3 Primary Support Contact.  It comes up with my details but straight away error appears ! We couldnt update your contact details.  Try again later.   I have tried leaving them, updating them and used Edge and Chrome, I am unable to proceed.  Any other suggestions?
Registering SCG fails. We couldn't update your contact details. Try again later