When trying to connect your mail to outlook you might run into this certificate error.
There is a problem with the proxy server’s security certificate. The security certificate is not from a trusted certifying authority. Outlook is unable to connect ot the proxy server mail.company.com (Error Code 8).
The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete action.
You need to install the certificate. If you are on same network outlook will give the option to install the security certificate, otherwise get it an install it and the it’ll pass the security correct.