As an IT professional for over 20 years I have run into a lot of strange errors in my time. I also have an extensive home “production” lab so I can stay up to date on changes in tech and its fun! Recently I installed Exchange 2016 in a Hyper-V virtual machine. It was a simple migration from 2013. I was in the process of decommissioning an older Hyper-V host. Some of my guest vm’s were migrated while others were built from scratch.
I had completed my migration and Exchange, OWA, & ECP were working just fine. About a month later I tried to access the ECP and was greeted with a 500 Error!