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While trying to make a WCF service to connect Dynamics 365, I came across to this error message:


Message Metadata contains a reference that cannot be resolved: ‘’. >> StackTrace at System.ServiceModel.Description.MetadataExchangeClient.MetadataRetriever.Retrieve(TimeoutHelper timeoutHelper)rn




We also saw the error below during testing:


InnerException System.Net.WebException: Unable to connect to the remote server —> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond


Root Cause


Dynamics 365 started requiring TLS 1.2 after version 9.x (Reference). Connections that don’t use TLS 1.2 started failing after this update.




Force WCF service to use TLS 1.2 to solve this issue:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

Brought to you by Dr. Ware, Microsoft Office 365 Silver Partner, Charleston SC.