THE WINRM CLIENT RECEIVED AN HTTP STATUS CODE OF 502 FROM THE REMOTE WS-MANAGEMENT SERVICE.

Found error when open the Exchange Management Shell on exchange 2013.

Connecting to remote server failed with the following error message : The WinRM client received an HTTP status code of 502 from the remote WS-Management service.

Solution: 
Open command prompt and run the command below;

netsh winhttp reset proxy

https://technet.microsoft.com/en-us/library/bb430772(v=exchg.141).aspx