[WCF] System.ServiceModel.ProtocolException

Exception message:

An unhandled exception of type 'System.ServiceModel.ProtocolException' occurred in mscorlib.dll

Additional information: Content Type text/xml; charset=utf-8 was not supported by service XXX. The client and service bindings may be mismatched.

Possible Solution:
Change WsHttpBinding (default binding) to BasicHttpBinding.

Ref: Difference between BasicHttpBinding and WsHttpBinding. Possible reasons: Compatibility. BasicHttpBinding is there only to support the old .ASMX style of working.

Now everything is OK :-)