UPDATE: This has been resolved by a Microsoft update
If you have recently added a SIP domain to Lync 2013 and you are pulling your hair out because you cannot sign-in externally, then here’s what you need to know….
Being a Lync hoster we need to add SIP domains on a regular basis (well our provisioning engine does). In Lync 2010 a new SIP domain could be provisioned and enabled in the time it took for CMS replication to occur. As of Lync 2013 RTM this is no longer the case; now every time a SIP domain is added the Edge server Access Edge service needs to be restarted before you can login using the newly added SIP domain.
This is less than ideal when you operate a highly available hosted Lync platform! To this date I have not been able to find a solution to the problem, nor have I been able to find a reason for this change – bug/design? If anyone knows something I don’t please let me know.
How do you know you have this problem?
Client Error
The Lync client will likely throw the following error message “The server is temporarily unavailable. If the problem continues, please contact your support team”
All I can suggest you is to open a support ticket against MS, and force them (IF THEY ACKNOWLEDGE this is a product defect) to fix this or at least document this behavior.
I think I might just do that!