Hi Guys,

I am in the process of upgrading my exchange 2007 to 2013. i now have setup a 2013 server successfully. However, i seem to be having problems with my exchange certificate. Everytime i open my outlook it comes up with the dialogue gox below

The old server is still in the envirnoment so i was thinking its certificate is the one being picked up. could this be that the CAS is still on the old server? if yes, how to i transfer it. if otherwise, please assist.

Regards,

BJ

Try going into Control Panel>Internet Options>Connections>LAN Settings and see if the "Use a proxy server" box is checked. There has been a piece of malware, usually called BrowserSafeGuard with RocketTab that has been setting proxies on computers. 

That program usually comes with a cocktail of other malware as well such as MaxWebSearch and Optimizer Pro. You can try to remove them by first uninstalling them in your Programs and Features, then going into the AppData\Local folder and AppData\Roaming folders and deleting their installation folders, then going into the registry and removing any instances of them there. Be especially wary of the HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce which typically has a re-install script for when the user logs in.

If you don't see any of those things, just uncheck the box, and the issue should be resolved.

Let me know if this was the issue!

Did you get a third party cert with the appropriate subject names? 

Typically mail.company.com and autodiscover.company.com

Once you do that, make sure you have rehomed all your web services to reflect those names using the article below.

Outlook 2007 security warning: "The name of the security certificate is invalid or does not match the name of the site"
https://support.microsoft.com/kb/940726

Hi,

I suggest try to re-create profile to refresh the caches for testing.

If doesn't work, please try to check following checkpoints:

1. Open IE and browse RPC URL, https://mail.domain.com/rpc, to examine the certificate.

2. Install the trusted root certificate.

3. Disable the 3rd party add-in or the 3rd party browser add-in.

More details to refer following KB:

Error message when Outlook tries to connect to a server by using an RPC connection or an HTTPS connection: "There is a problem with the proxy server's security certificate"

https://support.microsoft.com/kb/923575?wa=wsignin1.0 

Also provide an FAQ for your reference:

Checklist for Exchange Certificate issues

https://social.technet.microsoft.com/Forums/en-US/fa78799b-5c55-4c71-973b-0e186612ff6f/checklist-for-exchange-certificate-issues?forum=exchangesvrgeneral