We use Outlook2007 on non-domain connected clients and support multiple email domains , domain1.com and domain2.com. Domain2 is a Secondary external domain in our Exchange environment and the domain for our primary SMTP email address. We need to get our CAS servers to accept autodiscover.domain2.com connections from our clients. Their email addresses are firstname.lastname@example.org,, etc... While their domain accounts are in domain1.com. The autodiscover website is not requiring SSL but we still get the certificate error when starting outlook, and are unable to download the OAB. Any help is appreciated, thanks.