Error Message :
No Exchange servers are available in any Active Directory sites. You can't connect to remote Powershell on a computer that only has the Management Tools role installed. It was running the command 'Discover-ExchangeServer -UseWIA $true -SuppressError $true -CurrentVersion 'Version 14.1 (Build 218.15)".
3. On exchange server, run DCDIAG to check your Active Directory and Domain Controllers and check if there is any error.