Outlook plugin not working

Outlook plugin not working

All my users are getting this error when attempting to access the Content Central Integration for Outlook plugin.

I have uninstalled and reinstalled. Tested with Outlook Desktop client and Outlook web. Same result. I have tried on different networks to avoid the firewall. Same result. 

Ademero Support could not figure it out either. It feels like it's on Ademero's side. Is anyone else's outlook plugin working with the latest version of Outlook?

Last thing to mention, it was working fine and no changes were made to our system.