SIP Error "500 Overlapping transaction not allowed"


I have an issue with attended transfer, sometimes it fails, when comparing the wireshark traces for working and non-working cases I found this Error message “500 Overlapping transaction not allowed”.

Could you please advise what can be the cause of this ?

Thanks in advance.

What version of Asterisk? What channel driver are you using (if 13)? What is the SIP trace (sip set debug on, or pjsip set logger on - depending on channel driver).


I’m using an appliance with Asterisk 1.8 built-in. The trace is captured using wireshark .


You weren’t asked how you obtained the trace, but for its contents.

Note that it is easier for people to look at traces if the are included as text in the report, so wireshark is not the best way of getting them.

Also, Asterisk 1.8 is past end of life, although my guess is that this is a fussy peer rather than Asterisk.


Thank you all for your answers, the issue has been resolved.

This is caused by SIP Overlap Dialing option, when it’s disabled all work just fine.

Thanks again.