When you attempt  to install Dynamics 365 App for Outlook, you encounter the following error:
"There was an issue when attempting to add the app to Outlook.
SoapException : GeneralIncomingEmailServerError"
If you click the Details link, the following additional details appear:
 "Error : System.Web.Services.Protocols.SoapException: The specified server version is invalid.   at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)   at System.Web.Services.Protocols.SoapHttpClientProtocol.EndInvoke(IAsyncResult asyncResult)   at Microsoft.Crm.Asynchronous.EmailConnector.ExchangeServiceBinding.EndInstallApp(IAsyncResult asyncResult)   at Microsoft.Crm.Asynchronous.EmailConnector.OfficeAppsDeploymentStep.EndCall()   at Microsoft.Crm.Asynchronous.EmailConnector.ExchangeIncomingEmailProviderStep.EndOperation()"