Solved Cannot hear incoming calls sometimes

[AEGIS_SEC_SOL]

I have a 3cx system hosted on amazon light sail. Sometimes incoming calls cannot be heard by the person picking up the phone, when they hang up and dial again we are able to hear. Any suggestions on resolving this issue. I have GRP2614 & 2613 phones. Professional 16.0.5.611 version.

 

[leejor]

You have not provided any information on how the sets/location are/is provisioned. Do they use STUN? If so, how many sets at that location? Does the site use an SBC?

 

[AEGIS_SEC_SOL]

Sorry, they use STUN, I have 24 Sets/extensions at the location. No SBC

 

[leejor]

This may be the issue. Was it set up according to 3CX documentation on using STUN extensions?

https://www.3cx.com/docs/manual/configuring-ip-phones/#h.ul2fzupi6t22/

Was each set assigned a unique local port? Were all audio ports forwarded, as needed, in the local router? Was PBX Delivers Audio, enabled on each extension?

Why, with that many extensions, at one location, did you not use a 3CX SBC?

 

[JohnS_3CX]

More importantly, if your webclient does not face the same issues, its quite likely what @leejor suggests to check

 

[AEGIS_SEC_SOL]

Thank you @leejor & @JohnS_3CX, I did not setup unique ports, Do all the sets need to have unique SIP & RTP ports or just SIP only? Do you think it'll work fine if we set them up on unique ports or do we have to implement SBC?, if we do implement SBC then can the ports remain default?

 

[JohnS_3CX]

With SBC you do not have to worry about port forwarding at all.

With STUN phones, the need unique SIP+RTP ports, then those ports also need to be forwarded individually on the office firewall, then you also need to enable remote extension registration in each extension, and PBX Delivers Audio in each extension. If this is a couple of phones ok, but as you see the more phones you have the more work needs to be done. Generally SBC makes life easier on the admin because all that can be avoided, plus you can remotely provision reseted deskphones, as well as have encryption enabled as standard for audio and SIP traffic

 

[leejor]

For a relatively low cost, I would suggest installing the Raspberry Pi SBC, to avoid the issues you are having now, and possibly in the future. Each, will support up to 30 sets.
https://www.3cx.com/docs/3cx-tunnel-session-border-controller/

 

[AEGIS_SEC_SOL]

thank you @leejor. changing the ports on each set helped the issue for now. Will be implementing SBC soon.