Forum Discussion
Suspicious events
Exchange 2016 fully patched. Saw a few errors in Application log. Source: MSExchange Front End HTTP Proxy [Owa] An internal server error occurred. The unhandled exception was: System.ArgumentEx...
I have also started seeing these on my Exchange 2016 server that is fully patched with the latest CU. The errors are identical to yours. I have not been able to determine what these are and I've opened a support request with Microsoft to see if they can help figure out what is going on. This started on Saturday the 6th for me.
Since most of our users are on mobile device I start to block external access to OWA with IP Address and Domain Restriction. ECP is already on secondary IP address without internet.