Recently, we ran into an unusual problem with provisioning Lync Online users in Office 365 — we’d enabled Lync for some users but those users were unable to login to Lync. Fortunately, the fix turned out to be rather simple (though not particularly obvious).

First, the problem: User accounts we’d provisioned for Lync couldn’t sign in, and received this “sign-in address not found” error from multiple computers on multiple networks:

In addition, we observed that users logged in via OWA had Lync services showing up but they weren’t available.

Just to make sure we’d done everything right, we double-checked that users were properly licensed to use Lync in the admin portal. Sure enough, everything appeared as it should:

 

The solution to this conundrum, as outlined to us by Microsoft Online Services, is to open an elevated command prompt on a machine with the latest Lync and Office365 pre-requisites installed and run “>ipconfig /flushdns” and “>ipconfig /registerdns” as shown below:

Next, open the Lync client and in Options > Personal > Advanced… manually input the appropriate connection settings for Lync for Office365:

After doing the above, you should be able to connect to Lync using the client you just configured. Once working, you can go back into the settings and reset it to simply connect automatically — it should continue to work. Shortly after taking these steps (5-10 minutes), Lync services should also be available in Outlook Web Access as well.

Hopefully this documentation will help others who run into similar issues.