Unknown Music Playing When Dialling Local Numbers

[Belal Khaled]

Hi team,

I've been running through several sets of solutions to get an issue, that we've been facing for over 2 weeks now, solved and can't seem to wrap my head around it.

Issue:
- When dialling local numbers from a provisioned landline/web client, we hear "waiting" music playing after a few rings. It's as if someone has answered our call and put us on hold.
- The issue occurs on landline and 3CX Web Client
- Sometimes when dialling a local number from our hard phone, we can hear the ringing tone, but the receiver doesn't get any call.

We're using the latest stable release of 3CX (v 16.0.8.9) and using Google Cloud for hosting.
I've checked the outbound rules, SIP trunks, analyzed SIP packets for troubleshooting and they were okay.
Firewall checks were perfect with no issue.

Everything else works - we can make international calls and receive them too. This issue happened recently and it was working perfectly a few months ago.
Nothing has changed and yet we started hearing "waiting" music when dialling local numbers. We're using a Singaporean number.

Example in the form of scenarios:

Scenario #1:
1. international user dials our telephone number.
2. We pick up the call and we can communicate.

Scenario #2:
1. Local user dials our telephone number.
2. They hear music playing and our phone doesn't ring,

Could this have something to do with the regional rules applied? Could it be a problem with provisioning?
Please let me know if there is any more information I can provide to facilitate the search for solutions.

Looking forward to your help - thank you so much in advance.
I'd be happy to provide sample ".pcap" files if it could help narrow down the problem.
I've analyzed them and don't see any red flags in comparison with making international calls.

Best Regards,
Billy

 

[VasilisV_3CX]

Hi @Belal Khaled,

I've reread this and there is a conflict here, in the beginning you mention you call out and hear the music, in your examples you're receiving calls, could you clarify which one is causing the music on hold?

If you're dialling out, this most likely will have been sent by your provider, I'd suggest asking them.

If your caller is hearing MoH, and you're not receiving the call then, when a local external call comes in, where is it going to? You can see this from the switchboard for example.

 

[Belal Khaled]

Hi Vasilis,

Thank you for your input. To clarify, the music seems to be coming from calls being made between 3CX and the caller in the local region only (Singapore)

The table below demonstrates how the issue occurs:

From: Caller (Mobile Carrier)	To: Receiver (3CX)
Local Number (Singapore)	Local Number (Singapore) => Music Plays
International Number (Malaysia)	Local Number (Singapore) => Works Fine

From: Caller (3CX)	To: Receiver (Mobile Carrier)
Local Number (Singapore)	Local Number (Singapore) => Music Plays
Local Number (Singapore)	International Number (Malaysia) => Works Fine

Apologies for not being clear earlier. I suspected this might have been an issue with the provider but it only happens in the local region so I cannot get to the bottom of the problem. I'm looking at the switchboard and calls are coming in and out like it always is, which makes this issue more peculiar.

 

[VasilisV_3CX]

Hi @Belal Khaled,

I think the first point of support you should contact here is your provider, and mention to them that this music plays and you're not sure why as you've not enabled it. They should be able to tell you if it's a value added service or something that shouldn't be happening.

 

[VasilisV_3CX]

Hi @Belal Khaled,

Before doing that, could you tell me who your provider is?

Also in the Management Console >> SIP Trunks >> Select your Trunk >> Options >> Advanced section >> Check PBX Delivers Audio and make sure Support Re-Invite and Support Replaces is unchecked, then test again.

 

[leejor]

I know that in the past (they may still do it), some mobile operators in the US were offering to replace the ringback tone, on outgoing calls (and maybe incoming), with music of your choice.

I don't think it was that popular, and have not recently heard of it being promoted. It might be something that your provider offers, and for some reason, assigned it to your trunk group, without being asked.

 

[Belal Khaled]

Hi @Belal Khaled,

Before doing that, could you tell me who your provider is?

Also in the Management Console >> SIP Trunks >> Select your Trunk >> Options >> Advanced section >> Check PBX Delivers Audio and make sure Support Re-Invite and Support Replaces is unchecked, then test again.

View attachment 22817

Hi @VasilisV_3CX,

Many thanks for your suggestions - our provider is Plivo.

I've already made sure that the option "PBX Delivers Audio" is checked while "Supports Re-Invite" and "Support Replaces" are unchecked.

I've contacted Plivo support as well to ensure that this was not an issue from their end.

 

[Belal Khaled]

I know that in the past (they may still do it), some mobile operators in the US were offering to replace the ringback tone, on outgoing calls (and maybe incoming), with music of your choice.

I don't think it was that popular, and have not recently heard of it being promoted. It might be something that your provider offers, and for some reason, assigned it to your trunk group, without being asked.

Hi leejor,

Thank you for your input. We're suspecting this might be from the provider themselves, but we're unsure so I've contacted them regarding this matter and checking to see if there's something we're missing.