I have a Multi-SAN certificate issued by Godaddy which has four subject alternate names.

to use this in an Exchange environment, I have added the external hostname and internal hostnames of my exchange box as SANs - so both internal and external OWA users can access the server without certificate errors.

I have now added a Lync server to the environment, and popped the same certificate on that machine, hoping to use one of the other SAN names to provide that service.

Lync users can connect fine, and all seems well - but OWA integration just fails outright, with the "Instant Messaging is not available right now" error message.

I suspect that the fact that the same certificate is on both the OWA box, and the Lync box (albeit referencing different SANs of the same cert) is the problem.

Any suggestions?

  • It seems like the solution is obvious from the problem as stated; Get a new cert for the Lync box. Is there something missing from the problem statement? Have you looked for error messages (e.g. in the Event Log)? Sep 3, 2011 at 21:41
  • 1
    Why do you believe the certificate is the problem? Have you considered setting up a self-signed certificate temporarily to see if that is really the problem? I have seen the same wildcard certificate used on several hosts, and they didn't have any problems communicating.
    – Zoredache
    Sep 4, 2011 at 5:32

2 Answers 2


There is no problem at all in using the same certificate in two different applications, if everything else is ok. The certificate in itself is not the problem, the problem lies in some misconfiguration on the Lync side.

You should check all URLs Lync uses (they are a lot...), and verify that your certificate actually contains all the names being used. Also, you should check everything else... DNS, firewalls, FQDNs, updates, event logs... there are literally tons of things that can go wrong when setting up Lync, and can have side effects ranging from "quite understandable" to "totally crazy".


You'll need to re-key your GoDaddy Certificate to include all the name. What I'd do in this scenario is request a new certificate on my exchange server but this time include the names needed for Lync. Make sure to mark the private key as exportable. This can be done using the PrivateKeyExportable parameter if you are using the Exchange Management Shell.

Once you have have the new certificate on the Exchange server you can export it with the private key, then import it into Lync.

  • Looks like he has all the right subjectAltNames in there
    – Ram
    Jun 14, 2012 at 22:06

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