Issue: Error message from Outlook: There is a problem with the proxy server’s security certificate, %s. The name on the security certificate is invalid or does not match the name of the site. Outlook is unable to connect to this server. (%s)
Finding/Resolution: Checked Outlook provider settings and saw that server and certificate was set to 2 dashes(–)
used this command to fix: set-outlookprovider EXPR -Server $Null and Set-Outlookprovider EXPR -CertPrincipalName $Null
The command will set outlook provider EXPR to Null(Blank). By doing so Outlook will rely on autodiscover to get the correct outlook anywhere settings
Ex-Shell 