If you get “Connection to remote server” / “ClientAccessServer = EXCHANGE, BackEndServer = EXCHANGE” error while opening Exchange Management Shell on your Exchange Servers and the Management Shell connects to another server that is a member of Exchange DAG.
If you get Event: 15021, HttpEvent error in the event logs like the following;
Open IIS Manager –> Sites –> Exchange Back End Sites
Check you https protocol “Exchange Back End” Binding
There is a must be self-signed “Microsoft Exchange” certificate here, if not here , it may have expired and you need to renew it on the Exchange ECP console or MMC console.
Have a nice day!