- You are using Lync Online together with Lync or Lync Basic client.
- You’r client is joined to an Active Directory domain with Single Label Name (SLD). FQDN Name is, as an example, “domain” and not “domain.local”
- You can logon to Lync using mobile clients or from other clients than are not domain joined to your Single Labeled Domain.
- When logging on with the Single Labeled Domain joined machine, the Lync Client gives the following error:
The Server is temporarily unavailable. If the problem continues, please contact your support team.
Single Labeled Domains are not supported with Lync Server, but there is no documentation regarding Lync Online instead of an on-premise Lync installation in combination with a client running from a Single Labeled Domain.
The fact is that this combination does not work wihtout additional configuration (see Resolution). Allthough the Lync Online infrastructure is not running in a Single Labeled Domain, the client can’t login from a machine joined to a Single Labeled Domain.
To solve this, all users that are running Lync Online must have a proper UPN-suffix in Active Directory. There is NO NEED to login with the UPN-name, but the attribute itself must be populated.
Follow these steps to verify the solution with a few users, before applying to all users:
- In you Active Directory forest, add an additional UPN Suffix. As suggestions to what to add, you can add the same as your SMTP domain(s), or just use the current SLD and add “.com”. Instructions on how to add UPN Suffix can be found here: http://support.microsoft.com/kb/243629
- On your own (an/or other) user account(s), change the UPN Suffix to the newly added “domain.com-like” using Active Directory Users and Computers. You find the UPN suffix on the Account tab, the right drop-down box under “User logon name”
- Wait for AD Replication to complete (15 minutes give or take, depending on number of AD sites etc.)
- Log off and on to your workstation
- Attempt to log in to Lync again
- Repeat for remaining users
With a correct UPN Suffix, Lync Online will allow you to log on from the domain joined machine, regardless if you logged in with your samAccountName or the full UPN-name.