Client found response content type of '', but expected 'text/xml'.

Today we experienced ‘another’ issue with the Microsoft CRM 4.0 Email Router Configuration Manager. Like many of the other issues with the E-mail router tool, we only noticed when we stopped receiving email association icons in outlook.

Normally for us this has ended up being the problem with the Configuration Manager xml configuration files, and has required us to restore them from backup in line with the Official MS fix.

Unusually today the error lay elsewhere. With a test of the User and Queue access, we were receiving a message that looked like this:

• Client found response content type of ”, but expected ‘text/xml’.

With an Event Log Entry Event ID: 0

• #26090 – An error occurred while opening mailbox email@domain.com System.InvalidOperationException: Client found response content type of ”, but expected ‘text/xml’.

  The request failed with an empty response.

     at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)

     at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)

     at Microsoft.Crm.Tools.Email.Providers.ExchangeServiceBinding.GetFolder(GetFolderType GetFolder1)

     at Microsoft.Crm.Tools.Email.Providers.ExchangeWSConnector.OpenMailbox()

     at Microsoft.Crm.Tools.Email.Providers.ExchangePollingMailboxProvider.InitExchangeConnector()

     at Microsoft.Crm.Tools.Email.Providers.ExchangePollingMailboxProvider.OpenMailbox()

     at Microsoft.Crm.Tools.Email.Providers.CrmPollingMailboxProvider.Run()

The long and the short is that we are using Microsoft Exchange Server 2010

With an Email Router Configuration setup for the Rollup 9 supporting Exchange 2010 with Windows Authentication. The URL for the location of the exchange server in the Profile tool looks like this:

https://server/EWS/Exchange.asmx

Hitting that URL should normally reveal some XML data about the email box being interrogated:

While the CRM Router Service was in error, the URL returned a blank result. This indicated that the Exchange Server 2010 service was at fault. The short term solution was to reboot the Exchange Server. We are yet to track down the exact cause.

Bottom Line… Errors like this appear to be pointing to invalid data return from the Exchange Mail Server.