CX600 hangs up after 10 seconds when calling Lync 2010 voicemail

[Anonymous]

We have a Lync 2010 system, it works fine on site. The system works quite well off site as well, with the sole exception being the CX600 phones. I can call voicemail from the phones on site and they work, but if I try from off site it hangs up after 10 seconds. Using a cell phone, a land line, or the Lync client will work fine, but trying to use the CX600 fails every time. Any ideas?

I have tried this with an HP phone, the HP phone seems to work off site.

[SteffenBaierUK]

Hello ,

welcome to the Polycom Community.

So this only happens when you call from a CX600 to the VoiceMail system of the site?

• Are the phones running the lastest release of their software?
• Are these phones stand alone or connected to a PC?
• Have you checked the LYNC server for the SIP logs?
• Have you contacted Microsoft yet?

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

[Anonymous]

• Are the phones running the lastest release of their software?

   - Yes, the phones are running the latest patch level.

• Are these phones stand alone or connected to a PC?

   -Yes and yes. I have tested as tethered and untethered, it fails in both cases.

• Have you checked the LYNC server for the SIP logs?

    I have checked, the only message I find in each failure case is:
     21; reason="Call failed to establish due to a media connectivity failure where one endpoint is of unknown type";

• Have you contacted Microsoft yet?

    -Not yet, we are still running some Wireshark captures to see what the issue may be. Overall it's rather confusing - it makes little sense why the Lync client will work, cell and land lines work, just not the Lync Desk Phone.  The fact that the issue happens exactly 10 seconds after the VM server answers leads me to believe the issue is likely more of a failing syn/ack situation, and not necessarily the phone itself. If I find an answer I'll post it here, I can find many webpages and forum posts from people having the same issue, but I think saying it's a CX600 issue is misplaced blame, especially since i can recreate the issue now with Avaya phones as well.