Autodiscover works internally, but not externally?

Hey all,

Been having some issues with our autodiscover lately. Noticed problems when our off-campus locations were having troubles with outlook (e-mails getting hung-up in outbox, calendar sharing not working, etc) so I think I have the problem narrowed down to the autodiscover service.

Our mail server is set up as exchange.domain.com for internal and the external address is mail.domain.com (or https://mail.domain.com/owa for Outlook Web Access [which is working as far as I can tell]. Our website is using the same domain name: www.domain.com.

I checked the DNS and it seems to be fine, with a CNAME record for autodiscover pointing to exchange.domain.com.

Also checked permissions on the Autodiscover folder, seems to be fine, also rebuilt the autodiscover virtual directory in EMC and that still has not fixed it.

Checked IIS and the ports seem to be binding correctly, however the ExRCA says that port 443 is blocked or not giving the correct response.

Also checked the cert for the server and the autodiscover subdomain is listed as well.

When I run the ExRCA this is the result:



Any ideas on how to fix this? Would be greatly appreciated.