D(one) IT

IT Tips, Tricks & Such

PSTN to Lync 2013 Unassigned Number failure

Incoming calls from the PSTN to an unassigned number within the unassigned number range on Lync 2013, the call fails. The same number called from the Lync client completes successfully, and is routed to either the Announcement service or Exchange Attendant depending on configuration. In Snooper the call trace shows a “486 Busy Here” or “403 forbidden” or “404 not found” depending on your Gateway/PSTN provider.



Looking into the 403 forbidden message, I came across VOIPNorm’s Call Park Retrieval Issues From CUCM 8.x. It seems as though both the Call Park Service and the Unassigned Numbers are skipped for external inbound calls.

The fix is to create a trunk that has no PSTN usage records.




3 responses to “PSTN to Lync 2013 Unassigned Number failure

  1. Ian McBeth May 16, 2013 at 1:29 pm

    and I have learned something new today … Thanks Michael

  2. kbend April 3, 2014 at 2:49 pm

    Reblogged this on Kjartan's UC stuff and commented:
    A sidenote: if upgrading from lync server 2010, it will not be sufficient to redirect the gateways to the new 2013 pool. you have to delete the gateway(s) and trunks, publish topology, then re-add them to topology with 2013 pool, and publish again. be sure to update the pstnusage on the “real” trunk. Thanks to Michael for sharing this.

  3. Han October 9, 2015 at 3:56 am

    Thanks. This solved the problem with unassigned numbers for us.

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