strange CODEC NEGOTIATION ERROR

T

topogigio

Member
Jun 17, 2019
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Hi,
I have a PBX running well, but a single phone cannot call. The phone is a Yealink T33G.

Every time it tries an outgoing call (to external o internal recipients) it fails with CODEC NEGOTIATION ERROR.
CDR reports always PCMA/PCMA as codec, that is ok.

Calls TO this phone work well.

I was forced to connect the phone using TCP instead UDP as transport beacuse using UDP it does not perform MD5 auth (strange), but I think this cannot be the problem.

Any idea?
 
Paste a complete log so we can see where the problem is. Also try to update the firmware. Older Yealinks have weird issues like that sometimes. You may have to hunt the internet to find it, though if the phone is discontinued.
 
Thank you and sorry for delay.

Firmware is the last one, updated a few months ago from Yealink 124.87.0.15

However I perfomed a factory reset of the phone, reconfigured account, and now.. it works. It cannot register using UDP and still requires TCP, but calls are accepted.
 
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UDP has a limit for the header size of the packet. SIP can easily exceed that limit. When the limit is exceeded then the packet doesn't reach its destination.
 
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