IP Phone cannot call back

[Kane Wong]

Hi all specialist;

Have you seen an issue like my case below, I am calling between two ip phone, the ip phone B is not in 3CX supported phone list. This is a SIP endpoint from other manufacturer.4

Actions
1) Yealink phone extension 1234 call IP Phone B extension 1115, call and talk is fine.

2) IP Phone B extension 1115 call back to Yealink phone extension 1234, not working, The user holding IP Phone B hear the "Doo Doo Doo Doo" tone.

when I talk to the IP Phone B manufacturer tech support, they say, there might be an issue from Proxy Server ip address and the port but I am using the same 3CX server ip address and the same port number 5060.

How can I troubleshoot this issue?

 

[JohnS_3CX]

Hi Kane,

If you are using an unsupported phone, you might still be able to get it to work only if you run captures and analyze the SIP messages to see what 3CX expects, and what the phone is sending. You can then use trial and error to change the settings on that phone in order to make it work. Alternatively, the manufacturer of the phone may have already tested it with 3CX and have their own settings they can give.