Hi Jacob,
Maybe you know this, our hosted (multi-tenant) exchange 2013 CU14 is using autodiscover redirect.
But suddenly it is saying the certificate name is incorrect because it is not the customers url.
I think it has something to do with autodiscover internal and external url. but I am not sure.
maybe you have some ideas?
I would suggest using the Microsoft Exchange test connectivity site for further troubleshooting. Remember that your autodiscover redirect server needs to have port 443 completely shut off. So your clients domain (clientdomain.com) should have autodiscover.clientdomain.com that points to (CNAME) your redirect server (lets say redirect.hoster.com).
redirect.hoster.com should have port 443 not open at all and it should redirect to https://mail.hoster.com/autodiscover/autodiscover.xml (just an example domain).
Another thing you may want to watch out for if their website has port 443 enabled and that SSL has expired. Remember Outlook checks the following in this order doing autodiscover requests (lets assume the domain clientdomain.com):
- SCP record (for internal AD)
- https://clientdomain.com/autodiscover/autodiscover.xml
- https://autodiscover.clientdomain.com/autodiscover/autodiscover.xml
- http://autodiscover.clientdomain.com/autodiscover/autodiscover.xml
- then SRV record
