Outgoing call - dial tone rings once, then goes silent

[cpe90]

We have the on-prem 3CX server.
For some odd reason, today, when we make outgoing calls, the phone dial tone rings once and then goes silent until the other party picks up or their voicemail does.
It doesn't happen when calling another extension internally, dialing out using the 3CX app, for the remote office staff behind SBC connected to the HQ through VPN, or dialing out using the conference room speaker phone (Yealink SIP-W70B).
It only happens on our desk phone (Fanvil X7C-V2 firmware 2.12.20) in our HQ and our 2N callboxes that are set up directly using SIP.

Steps we have done.
1. Reboot the 3CX server VM
2. Reboot the phones in HQ
3. Reboot the POE switch
4. Retest the firewall from the dashboard and came back normal

The current 3CX version is Version 20.0 Update 5 (Build 551 Release).

Any suggestions to fix this would be greatly appreciated.

To be honest, I really want to move back to v18. Can we do that 3CX?
It's more peaceful with v18.

 

[leejor]

Off hand, it sounds like some devices are responding to a SIP message, from your provider causing them to "cut through" the audio and, your provider is not sending an audible ring-back tone until answer. You might want to use Wireshark, or the 3CX Activity Log, in Verbose, to confirm the timing of this.

There may be an option, in the devices that are not working to your liking, that might be changed. It could also be a firmware issue on the sets.

Do you have more than one provider?

Who is your provider?

 

[cpe90]

I found the FIX, or at least the workaround.
Thanks to @JFACS on this thread.

Post in thread 'T54W/T58W choppy ringing audio'

Apr 7, 2025

Thanks for the reply.

It turns out I just needed to enable PBX delivers audio for each user and the ringback heard was normal throughout the call again. Guessing this was an artifact still working as it was before in v18 when that option was configured as a checkbox on the gateway setup and not necessarily for the individual users. For whatever reason, that started acting up, but is sorted now once I checked that off for all 130+ users.

We have a similar issue with the Patton.
When dialing out, it will ring once and then be silent.
And your solution FIXED it!

THANK YOU!!!

• cpe90

You need to check the box "PBX delivers audio" for every single user/options.
Yes, it sucks if you have a lot of users.
I'm not sure if 3CX will do something about it or not.

This v20 is similar to Windows ME or Windows 8 OS. Lol.

 

[RoryJ]

You need to check the box "PBX delivers audio" for every single user/options.
Yes, it sucks if you have a lot of users.
I'm not sure if 3CX will do something about it or not.

Why didn't you just use the bulk edit feature?

 

[cpe90]

Why didn't you just use the bulk edit feature?

Thank you for this.
Didn't even try it until you mentioned it.