I'm doing some consulting work for a web development company's client, and this problem has me completely stumped.
The client has their Outlook setup to look at the url
https://example.com/autodiscover/autodiscover.xml when setting up an account. In the past, the site had no autodiscover.xml, this would return a 404, and Outlook would instead try
https://autodiscover.example.com/autodiscover/autodiscover.xml, which worked.
The site previously had no SSL certificate and would redirect to the http version, which would return a 404. However, after adding an SSL certificate, the https version of the link works, and the autodiscover.xml link instead returns
autodiscovery must be provided a valid email address
The non-HTTPS version correctly returns a 404 error, but the HTTPS version returns the string above. Why are the two returning different results when they're the same address? This has made entire email accounts for them inaccessible, so they are wanting a fix for this ASAP.
I've tried searching through all the files in the Wordpress installation to see if anything was causing this and couldn't find anything. The site is a reseller package from Hostgator, so the cpanel didn't seem to have any settings regarding disabling autodiscovery for Outlook. The .htaccess file didn't seem to have any rules in it that should be causing this, either.
I'm completely out of ideas and am tasked with making sure their email is working again ASAP. Any help is appreciated!