Gradwell SIP Trunk - line is silent

[Mountainbikert]

Hi,

I seem to have a problem with Gradwell and hope to find some expertise here, since Gradwell can't help me with this.
Situation:

On-premise 3CX PBX, latest software release, firewall check - all green. Based in The Netherlands, we have a block of 100 DiD's at a SIP provider. Works well.

I needed 5 UK landlines for a remote office. So Gradwell provided me with a SIP trunk and 5 DiD's. I provisioned one of these numbers on a mobile phone. Works as intended, can call inbound and outbound. But when I attach one of the remaining UK DiD's to a Digital Assistant to provide a phone menu for users, the line is silent when you call it. The counter starts but that's it.
When I forward one of the menu options to an existing extension, that phone starts ringing but again, everything is silent. Parties can not hear each other. I also added one of the existing Dutch DiD's to that Assistant and when I call it, I hear the menu options. Gradwell confirmed that 711A codec negotiated successfully and there is communication with the PBX.

I'm out of options here. Can someone shed a light on this?

• 3CX Version, Professional 16.0.8.9
• Server OS Windows 10
• Is the 3CX Server Hosted and where? ON Premise
• IP Phone Make/Model/Firmware
• Provisioning Method: Local / VPN / STUN / SBC Local
• Trunk Provider or Gateway Make/Model Gradwell
• Has the Firewall Checker passed: YES
• Are custom Phone Templates being used: NO

 

[ChrisC_3CX]

1. When you say that you provisioned one of these numbers on a mobile phone, do you mean the main trunk number and that the PBX is routing the call to an extension provisioned on a 3CX mobile Client(iOS/Android)?

2. Edit the DID Inbound Rule that routes to the IVR and route it directly to an extension that is provisioned on an IP Phone or 3CX Client, do you get the same issue?

3. Are you using the default template for this particular SIP Provider? Have you made any configuration changes for this SIP Trunk other than the account details? If you are not sure, try deleting the SIP Trunk and recreate it.

 

[Mountainbikert]

Hi Chris,

1. The main trunk number ends in 56 and I have provisioned DiD 60 and it runs on Android.

2. No. I was assuming that I should at least hear the menu when I dial the DiD.

3. Default template but can try deleting and recreating it.

 

[ChrisC_3CX]

I see, so routing an affected DID directly to an extension instead of an IVR works?

Have you only created one SIP Trunk and then added the rest of the numbers under that SIP Trunk's DID section?

Also, please make sure that you have followed this guide to set it up: https://www.3cx.com/docs/gradwell-uk-sip-trunk/

 

[Mountainbikert]

I see, so routing an affected DID directly to an extension instead of an IVR works?

Correct!

Have you only created one SIP Trunk and then added the rest of the numbers under that SIP Trunk's DID section?

Also, please make sure that you have followed this guide to set it up: https://www.3cx.com/docs/gradwell-uk-sip-trunk/

Yes, only one SIP trunk. One DiD is the default number and the other four were added as DiD's in the +4420 format
I followed the guide to the letter. Everything is where it should be.

 

[ChrisC_3CX]

In that case, try restarting the 3CX IVR Service from within Dashboard >> Services. (I'd recommend doing this during out of office hours as all IVR connected calls will drop and system extensions will unregister)

If you still get the same issue I'd recommend troubleshooting further by running a packet capture on the 3CX PBX while replicating the issue in order to determine if audio is reaching and leaving the 3CX PBX's network interface.

How to perform a packet capture from within the 3CX Management Console: https://www.3cx.com/docs/capture-network-traffic/

How to troubleshoot using wireshark: https://www.3cx.com/3cxacademy/videos/advanced/basic-troubleshooting/

If you need additional assistance on troubleshooting this, I'd highly recommend contacting a reseller so that they can help you with investigating this even further: https://www.3cx.com/ordering/find-reseller/