CreateCrmService incorrect url, CrmService fails with 404 - Not Found

I deployed a plug-in today to one of our clients dev server only to get a strange “404 - Not Found” exception being reported. The exception was raised from the CrmService, the service object was returned from context.CreateCrmService so it should of been ok. Digging deeper I could see that the URL was pointing to localhost which is incorrect as it should have been the host header http://crm.mydomain.fqdn, as always Google had the answer.

I found a great post where George Doubinski has reflected the issue and highlights the CRM bug

There’s a hot-fix for the issue kb950542 at the time of writing this had to be requested from MS.