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OWA IM TlsFailure with Skype for Business

On March 20, 2017

Thomas Stensitzki | MVP

0 Comment

OWA, Skype for Business, TLS

Exchange Server

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Problem

When you integrate Skype for Business Server instant messaging with Exchange Server 2013 or Exchange Server 2016 you might encounter the following error in the OWA InstantMessaging log files.

ERROR:UCWEB Failure: Code=TlsFailure, SubCode=TlsRemoteDisconnected, Reason=\r\n
Microsoft.Rtc.Internal.UCWeb.Utilities.UCWException: Unknown error (0x80131500) 
---> Microsoft.Rtc.Signaling.TlsFailureException: Unknown error (0x80131500) 
---> Microsoft.Rtc.Internal.Sip.RemoteDisconnectedException: Peer disconnected while outbound capabilities negotiation was in progress 
---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host\r\n   
at System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)\r\n   
at Microsoft.Rtc.Internal.Sip.TcpTransport.OnReceived(Object arg)\r\n   
--- End of inner exception stack trace ---\r\n   
--- End of inner exception stack trace ---\r\n   
at Microsoft.Rtc.Signaling.SipAsyncResult`1.ThrowIfFailed()\r\n   
at Microsoft.Rtc.Signaling.Helper.EndAsyncOperation[T](Object owner, IAsyncResult result)\r\n   
at Microsoft.Rtc.Internal.UCWeb.UCWAuthenticatedEndpoint.OotyUserEndpointEstablish_callback(IAsyncResult asyncResult)\r\n   
--- End of inner exception stack trace ---\r\n   
at Microsoft.Rtc.Internal.UCWeb.Utilities.AsyncHelper.EndAsyncCall[T](IAsyncResult asyncResult, String methodName, T ucwScopeInstance)\r\n   
at Microsoft.Rtc.Internal.UCWeb.UCWAuthenticatedEndpoint.EndSignIn(IAsyncResult asyncResult)\r\n   
at Microsoft.Exchange.Clients.Owa2.Server.Core.InstantMessageOCSProvider.<>c__DisplayClass33.<SignInCallback>b__32(RequestDetailsLogger logger)

The log files are located at

\Program Files\Microsoft\Exchange Server\V15\Logging\OWA\InstantMessaging

Solution

The Exchange Server OWA host name must be the common name (CN) of the SSL certificate used securing OWA communication.

Example for a non working IM configuration

OWA host name: owa.varunagroup.de
SSL certificate CN: mobile.varunagroup.de

Example for a working IM configuration

OWA host name: owa.varunagroup.de
SSL certificate CN: owa.varunagroup.de

Description

This scripts checks multiple Exchange Server 2013 OWA web.config files for existence of IMCertificateThumbprint and IMServerName Xml nodes required for Skype for Business OWA integration.

This mostly required after installing a new Exchange Server Cumulative Update.

IMServerName is the FQN of the Front End Pool

IMCertificateThumbprint is the certificate thumbprint of the Exchange OWA certificate

Exchange Server 2016 stores the IM information in Active Directory.

Example

# Update all OWA web.config files to Skype for Business FE Pool myfepool.varunagroup.de and thumbprint 

.\Set-OwaIMSettings.ps1 -FrontEndPoolFqdn myfepool.varunagroup.de -CertificateThumbprint "1144F22E9E045BF0BA421CAA4BB7AF12EF570C17"