When trying to read messages in the inbox get XmlHttpRequest

When I try to read messages in my INBOX under Messages, I get the following error


I also get this when trying to read my TO:ME messages.

No issues reading ARCHIVES.

I’ve restarted ODOO (service odoo restart), that this did not fix the issue. I have also rebooted the server, again did not solve the issue.

There are no errors in the logs (odoo-server.log)

This is ODOO 8 running under Univention Corporate Server 4.0-3 errata336

Any suggestions?