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After installing OCS 2007 R2 you might receive an Office Communicator “Limited External Calling” error on all your OC clients.

Validation wizard on the OCS 2007 R2 front end server shows this error:

A/V Authentication Edge Server: Could not contact A/V Authentication Edge Server. To resolve this error, check for the following
1. The outbound proxy is reachable.
2. The outbound proxy and A/V Authentication Edge Server are in trusted server list of each other.
3. The outbound proxy and A/V Authentication Edge Server have valid certificates.
4. Conference Server certificate is valid.
5. A/V Authentication Edge Server Gruu is correct.

Also you are using Regional Settings other than English (United States) on the OCS 2007 R2 Access Edge server.

This is caused by a bug in OCS 2007 R2 with regional settings.

From MS Support I got this work around:

  • Log on to OCS 2007 R2 Access Edge Server
  • Change the regional settings to English (United States) Dont forget to Copy your language and regional settings to system accounts on administrative tab.
  • Add the RTCProxyService to the local administrators group
  • In another session; log in as the RTCProxyService users
  • Change the regional settings to English (United States)
  • Log off the RTCProxyService
  • Remove the RTCProxyService from the local administrators group
  • Restart the server

This procedure works

Also Joachim Farla has more on this bug:


I hope this helps,

Note: For more solutions for this error also see here:

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