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 mail.mydomain.com. Outlook is unable to connect to the proxy server. (Error Code 0)This just started happening this morning out of the blue but only to ONE user. Everyone else is fine. I tried this problematic user on different computers, same thing. The user can get into OWA just fine, it’s only Outlook being problematic. And again, the biggest thing is that it only affects ONE user. I found a bunch of generic solutions about actual certificate issues but none of that applies.
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Source : Link , Question Author : prl77 , Answer Author : Community
