(STEP 1 - FROM EXCHANGE MANAGEMENT SHELL - EMS)
Set-ClientAccessServer -Identity CAS_Server_Name -AutodiscoverServiceInternalUri https://mail.yourdomain.com/autodiscover/autodiscover.xml
Set-WebServicesVirtualDirectory -Identity "CAS_Server_Name\EWS (Default Web Site)" -InternalUrl https://mail.yourdomain.com/ews/exchange.asmx
Set-OABVirtualDirectory -Identity "CAS_Server_Name\oab (Default Web Site)" -InternalUrl https://mail.yourdomain.com/oab
(STEP 2 - RECYCLE IIS APPLICATION POOLS)
1.) Open IIS Manager by clicking Start, then enter inetmgr.
2.) Expand the server and expand Application Pools, then right-click on MSExchangeAutodiscoverAppPool, and select Recycle.
(SOURCE)
https://support.microsoft.com/en-us/kb/940726