One quite common error I faced during the Exchange 2010 era is the WinRM HTTP Error:

If i use the management tools GUI i get an error message saying:
“Connecting to remote server failied with the following error message: The WinRM client received an HTTP server error status (500), but the remove service did not include any other informaition about the cause of the failure. For more information, see the about_Remote_Troubleshooting Help topic. It was running the command ‘Discover-ExchangeServer -UseWIA $true -SuppressError $true’.”

Using the Exchange Management Shell is get a similar error:
“Connecting to remote server failied with the following error message: The WinRM client received an HTTP server error status (500), but the remove service did not include any other informaition about the cause of the failure. For more information, see the about_Remote_Troubleshooting Help topic.
+ CategoryInfo : OpenError: (System.Manageme….RemoteRunspace:RemoteRunspace) [], PSRemotingTransportException
+ FullyQualifiedErrorId: PSSessionOpenFailed”

FIRST THING YOU MUST DO: DO NOT PANIC !
DO NOT REBOOT THE SERVER !!!
I WILL EXPLAIN HOW TO SOLVE THIS IN A FEW EASY STEPS:

1. When you open the EMC ( Exchange Management Console ), you will get an error similar to this: 

2. Go to START / Administrative Tools / Server Manager / Features / Add Features / And check WinRM IIS Extensions / NEXT / NEXT / CLOSE:
!!! IF YOU ALREADY HAVE THIS ROLE INSTALLED, JUST REINSTALL IT ! 

3.  Close / Reopen EMC and it will work like a charm ( NO REBOOT REQUIRED ):

ENJOY.

And if you encounter any problems feel free to comment / contact me.