Outbound - no reply to our critical packet - freezed phone

Hi everyone,

I found no similar issue in the forum, so I create a New Topic.

My System:
Asterisk Version: 11.17
Phones: SNOM 320 (
the Phoneserver and the Phones are on the same Network
Phones are “Direct” Connected to a Cisco PoE Switch

since last week (no changes on the Firewall and no changes on the Asterisk Server) sometimes when Our Employees do a outbound Call some of the Snom 320 freezes and at the same time I see the following Message in the FreePBX log:

chan_sip.c: Hanging up call xxxxxxxx - no reply to our critical packet

after some minutes the Phone is back or it restarts.

It concerns no special Phones or places (as I currently know) and it is always another phone.

Can anyone help?


That’s usually an indication of a network failure.

Check your switch. There are lots of possible problems, including too many “off hook” devices causing the power to fade, a bad connector somewhere, or an intermittent short in your infrastructure.

Thanks Dave,

I will check the switch With the network guys again. If I have new information I will add a comment.

no result from Our switch. Issue is since 26 days away. If it come back I will let you know.

I found the issue, we have every month a Vulnerability Scan. I dont know why but if it is running the Phones lagge and have disconnections.

What do you mean Vulnerability Scan?

We have every month a Client scan running, it checks open ports and software Security breaches on Our servers