A Unified Communication Blog
Get Adobe Flash player

Office Communicator displays the following warning to users:

some calls to and from people outside of your corporate network may not connect due to server connectivity problems. Try Signing out and signing back in. If this problem continues, contact your system administrator with this information.

This is most often because of faulty configuration of the Front-end and Access Edge server.

Verify the listening ports of the Access Edge server and the Front End server that they match.
Verify connection on the specified port (do a telnet on the A/V port)

Let me know if you have any probles (post comments below)


I have seen this error many times out there. Its to do with the Mediation server that is unable to contact the A/V Authentication server on the OCS Access Edge server. There are many reasons for this, there being a lot of places to set the references for Mediation, FE and Access Edge server.

Heres some places to look:

- Verify that alle Mediation servers are added to the Access Edge servers “verified” internal servers list
- Verify that alle Front End servers are added to the Access Edge servers “verified” internal servers list
- Verify that the A/V Authentication server is configured on the Mediation Server (and pointing to the Access Edge server holding this service)
- Verify firewall configuration by telnet to the A/V aut. port from the Mediation Server
- Verify that the Access Edge server is configured on the Mediation Server and Front End Server

Please continue to comment

For OCS 2007 R2 problems, also refer to this post:

0 Responses to Office Communicator "Limited External Calling"

  • Did you ever find a solution to this? We are having the same problem.

  • Hi Billy,

    This is a common error and can be caused by many things. I have updated the article above with some steps to verify your configuration.

    I hope it helps



  • Originally, I didnt put our mediation server into the list on edge, but still it worked fine. I find it very confusing, as there is not a single word mentioning meidation server in the Edge Server Deploy guide.

    Sometimes I saw the “limited external connectivity” warning, but that was most of the time because of poor network connectivity between mediation and edge server.

  • I had this error… I had not used FQDN of the internal OCS server on the Edge Server…. changing it fixed it!

    Make sure you use FQDN on all instances where server names are specified.

  • For me I could ping the server name but not the FQDN of the edge server because it was not part of the domain. I just added the FQDN to the host file and everything works fine now.

  • Great, Thanks for posting!

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>


Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 77 other subscribers

Follow me on Twitter