Yealink Forums

Hello support,

I have the following issue with yealink T20P sip phone

The phone have the latest firmware 9.72.0.25

When a call is made, it hangs up after 20 seconds.

In the PBX logs (my telephone core application runs with asterisk) I see this messages:

[Mar 10 16:16:35] WARNING[2919] chan_sip.c: Maximum retries exceeded on transmission 605946181@xxx.xxx.xxx.xxx for seqno 2 (Critical Response) -- See doc/sip-retransmit.txt.
[Mar 10 16:16:35] WARNING[2919] chan_sip.c: Hanging up call 605946181@xxx.xxx.xxx.xxx - no reply to our critical packet (see doc/sip-retransmit.txt).

xxx.xxx.xxx.xxx stands form telephone ip

I try with several devices with the same result, the problem disappear if I downgrade to 9.70.0.150 firmware

Is there a known issue like this ?
I googled and the problems came up because some of the SIP packages are not responded by the phone so asterisk hangs up the current call.

Thanks in advance for your support.
Best Regards

In order to do more troubleshootings with sip message, please supply me pcap files of 9.70.0.150 and 9.72.0.25. How to Get the Correct Syslog, Config.bin and Trace

Thanks for you response,

I enclose the required files,

The call was made from extension 113 to 100 and after 20 secs the call hangs up
I downgrade the phone to the 9.70.0.150 firmware and the problem disappear.

Thanks in advance

Thanks to your files. I have submitted to our R&D.
It would be better that you can supply pcap file of V70.

I send files from a call with 9.70.0.150 firmware from extension 113 to 109.
The call ended normally.

Thanks in advance

Thanks to your files.

Hi ajerez,

Please test below firmware which has solved your issue.
9.72.0.54.rom

Any feedback, please update for us. Thanks.

Thanks a lot for you response,

I will test it and let you know.

Best Regards

I test and with the provided firmware it is OK now, the calls are ended normally·

Thanks for our support,

Best Regards,

Thanks to your feedback.