If [ System.Security.Authentication.AuthenticationException ] is thrown, with [ RemoteCertificateNameMismatch ] , but it is confirmed/certain that:

• Certificate CommonName/Subject and/or SubjAltNames are containing the list of UFQDNs/FQDNs that the SOAP / WCF client is configured

• Trust anchors are in-place.

• Other Microsoft .net/ASP clients (Internet Explorer/Edge/etc.) have no certificate validation errors at the same URL endpoint.

In this case, we need/want dump , with DEBUG statements, the text/substrings that were expecting and what it found in the remote certificate (SubjAlName)during TLS handshake.

         “RemoteCertificateNameMismatch DEBUG: Expecting [ X (array of subjAltNames) ] but found [ Y ]”

Are these variables [X] and [Y] already already populated that we can debug/printf (log or Stdout) in the try{}/catch{} ?

We are working with a development subcontractor, and do not have direct access to code, but we want to assist them.