Cannot Sign In To Lync ERROR

An error that has been discussed number of times in various forums, as some of the articles which explains how to deploy a Lync Server doesn’t mention an important step. You get the error below while trying to sign in to the Lync 2010 client. “Cannot sign in because the server is temporarily unavailable. If…

An error that has been discussed number of times in various forums, as some of the articles which explains how to deploy a Lync Server doesn’t mention an important step.

You get the error below while trying to sign in to the Lync 2010 client.

“Cannot sign in because the server is temporarily unavailable. If the problem continues, please contact your support team.”

Cannot signin to Lync

An SRV record needs to be in the internal DNS for users to be able to successfully login to the Lync client. This step is missing in some of the articles out there which explains how to deploy a Lync Server.

Add an “SRV” record in the internal DNS for your SIP domain.

  • Service : _sipinternaltls
  • Protocol : _tcp
  • Port : 5061
  • Host : Lync Server FQDN

SRV Record for Lync Sign in

Once the record is in place, clear the DNS cache and you will be able to login successfully.

5 Comments

  1. shawn harry says:

    Depends on the AD topology as you may need a director server depending on how clients connect so they’re directed to the right pool. That said the best option is always SRV records unless you have an extenuating circumstance where you’d want to use a GPO.

    1. Rajith Enchiparambil says:

      Thanks Shawn.

  2. shawn harry says:

    Hey Raj you don’t actually have to have an SRV record. You can enter the FQDN manually or deploy via GPO. An SRV is just a nice to have to make the automatic configuration of the Lync client transparent to the end user. (certainly its a set up i always recommend) That said the error above can be for a variety of reasons :-)

    1. Rajith Enchiparambil says:

      Thanks Shawn.

      Yes, you can do it manually or using GPO. Which one will you pick, with the DNS route being the easiest one? ;)

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