When using cPanel AutoSSL and a remote email service, you may sometimes encounter a problem where outlook attempts to find the autodiscover info on the root domain instead of the actual autodiscover.yourdomain.com cname. For example: https://yourdomain.com/autodiscover/autodiscover.xml on startup. If an SSL certificate isn’t found there outlook then looks to http://yourdomain.com/autodiscover/autodiscover.xml and an xml isn’t found it finally looks for autodiscover.yourdomain.com, which is the correct place. However if a certificate is found in the first two checks outlook then checks to see if the certificate can be trusted. Since the SSL certificate from cPanel’s AutoSSL will not match the remote email service SSL, outlook will produce an error message.
To avoid this, you can create a simple htaccess redirect like so:
RedirectMatch 301 /autodiscover/ autodiscover.yourdomain.com