Earlier this year I spent significant time with a vendor troubleshooting requests we were sending across the network. In the end I was convinced of my need to rely almost exclusively on the vendor to verify that the certificate were correctly applied. Well, a colleague shared this link that describes how to configure network tracing for WCF service.
Configure Network Tracing
When troubleshooting complex systems never trust the well intentioned opinion of even the savviest technical mind, get the facts. This would have saved me days!