Exchange / Outlook - There is a problem with the proxy server's security certificate
After replacing a wildcard SSL certificate (*.domain.com) with a basic single-server certificate (webmail.domain.com) remote clients using Microsoft Outlook can no longer connect to their email accounts on an Exchange server using HTTP Proxy Method. Outlook displays below error and then repeatedly prompts for a password:
There is a problem with the proxy server's security certificate.
The name on the security certificate is invalid or does not match the name of the target site webmail.domain.com.
Outlook is unable to connect to the proxy Server. (Error Code 0)