Check your IIS certs and make sure you¹re not using a self signed one.
From: <listsad...@lists.myitforum.com> on behalf of Damien Solodow
Date: Wednesday, October 12, 2016 at 14:46
To: "Exchange@lists.myITforum.com" <Exchange@lists.myITforum.com>
Subject: [Exchange] Outlook certificate error?
We¹ve been intermittently finding an odd issue; Outlook will pop-up the
There is a problem with the proxy server¹s security certificate.
Outlook is unable to connect to the proxy server FQDN.
(Error Code 80000000).
Clicking Ok on the message gets rid of it and Outlook acts normal. I¹ve
looked at the Outlook connection status while the message is onscreen, and
it shows successful connections to HTTPS as well as usually a disconnected
one for the mailbox. OWA doesn¹t show any cert issues, and it¹s sporadic.
Exchange 2010 SP3, CU14 on Windows Server 2008 R2 SP1.k
Clients are Windows 7 SP1 x64, with Outlook 2013 SP1 x86.
Our CAS servers are behind an F5-LTM doing SSL off-load.
This isn¹t a new setup; the issue start occurring in the couple months as
far as I¹ve been able to determine.
Senior Systems Engineer
550 East Washington Street
Indianapolis, IN 46204