We have service that\'s working with small to large sets of data (document generation), and it\'s working fine for some calls, but for some specific requests (exact same method,
Check the name attribute of the service element in the web.config:
The service name should contain the correct namespace+classname.
You can find this in de code or by looking in the markup of the .svc file (or open the .svc file with notepad) for the Service="..." attribute.