Phones provisioned through SBC shows up on the PBX but extension fails to register

[Nkosiedread]

Hello all,

I'm trying to provision a Yealink T41s through the SBC but the the extension is failing to register.

The phone is appearing on 3CX phone dashboard and I assigned it to an extension but to my surprise the extension stays on red...

I tried to manually auto provision it by copying the URL directly to the phone confirm, then click autoprovision but nothing happens, the phone fails to download the configurations.

When I check the extensions there is no config file downloaded.


Below are the system details, I will appreciate any advsie/suggestion on what to check.

• 3CX Version, e.g. Standard Annual 16.0.8.9
• Server OS, e.g. Debian 9
• Is the 3CX Server Hosted and where: hosted on a private cloud
• IP Phone Make/Model/Firmware
• Provisioning Method: SBC version 16.2.24
• Trunk Provider or Gateway Make/Model: Generic
• Has the Firewall Checker passed: YES
• Are custom Phone Templates being used: NO

Thanks
Nkosana

 

[ClaudioBassani]

Check the phone has the correct firmware (https://www.3cx.com/support/phone-firmwares/) (https://www.3cx.com/sip-phones/firmware-update-yealink/)
Reset the factory default setting (https://www.3cx.com/sip-phones/factory-reset-yealink/) and try a new provisioning. This usually works.

 

[Nkosiedread]

Hi Claudio,


Thank you for your reply.

The phone is running the latest firmware version 66.85.05, 3cx phone dashboard confirms that too.
I did resetting but phone is not downloading config file, even if I manually force it using URL.

Anything else I can check ?

 

[NickD_3CX]

If you are manually inputting the Provisioning link in the phone and it is not 'pulling' any settings, that might point to a problem of the phone contacting the 3CX Server over HTTPS.

An idea, from the location where the IP Phone is located, use a PC and open a browser and try to download the provisioning file of the phone from there. For Yealink the link would be in this format:

https://<FQDN>:<HTTPS Port>/provisioning/<random folder name>/<MAC Address>.cfg

Example:
https://pbx.3cx.co.uk:5001/provisioning/akxdhfgjwe34f/ABCDEF123456.cfg

When you try to download this file from the browser, do you get an error or Cert Warning?

Also, your 3CX, is it using a 3CX FQDN/Certificate, or have you installed using your own FQDN and Certificate?

 

[Nkosiedread]

If you are manually inputting the Provisioning link in the phone and it is not 'pulling' any settings, that might point to a problem of the phone contacting the 3CX Server over HTTPS.

An idea, from the location where the IP Phone is located, use a PC and open a browser and try to download the provisioning file of the phone from there. For Yealink the link would be in this format:

https://<FQDN>:<HTTPS Port>/provisioning/<random folder name>/<MAC Address>.cfg

Example:
https://pbx.3cx.co.uk:5001/provisioning/akxdhfgjwe34f/ABCDEF123456.cfg

When you try to download this file from the browser, do you get an error or Cert Warning?

Also, your 3CX, is it using a 3CX FQDN/Certificate, or have you installed using your own FQDN and Certificate?

Hi Nick,

Thank you for your reply.

When I try to download the file I get an error warning (HTTP ERROR 404) page cannot be found.
I'm using a 3CX FQDN.


What could that point to ?

 

[NickD_3CX]

Well, first of all now we know why the phones aren't provisiioning, because they aren't getting the settings from the server.

From the same location where you tried to download the file from, can you access the Management Console in general? That would be https://<FQDN>:<HTTPS Port>/
If you can't even access that, then it is most likely an issue with the Firewall blocking the requests. Also just double-check that all 3CX services are running.

 

[Nkosiedread]

Well, first of all now we know why the phones aren't provisiioning, because they aren't getting the settings from the server.

From the same location where you tried to download the file from, can you access the Management Console in general? That would be https://<FQDN>:<HTTPS Port>/
If you can't even access that, then it is most likely an issue with the Firewall blocking the requests. Also just double-check that all 3CX services are running.

Hi Nick, I'm able to access the phone Management Console from the same location I'm not able to download config file. Check all the services from the pbx and there are all running.

 

[NickD_3CX]

Then check in your Extension Settings in the Phone Provisioning tab, have you correctly selected a Make/Model and input the MAC address?
Also, I think this is also the symptom if you are using a custom template and you have made a mistake in the template format.

 

[Nkosiedread]

Hi Nick, Just picked up this from the Activity logs

"03/09/2021 1:38:25 PM - [CM503003]: Call(C:86): Call to <sip:[email protected]:0> has failed; Cause: 487 Request Terminated/INVITE from 127.0.0.1:5080"
From the packet capture I can see the request to register from the phone and 3CX responds with proxy authentication required and the phones replies with unknown request.

 

[NickD_3CX]

I am a bit confused, if the phone fails to download any configuration, how is it registering? Did you manage to provisioned the IP Phone and get it to download the settings? Has the Extension Name/Number appeared on the display of the phone (to check if it downloaded the config)?

 

[Nkosiedread]

I am a bit confused, if the phone fails to download any configuration, how is it registering? Did you manage to provisioned the IP Phone and get it to download the settings? Has the Extension Name/Number appeared on the display of the phone (to check if it downloaded the config)?

Hi Nick,

The phone doesn't download any configuration.
Nothing appears on the Extension fields but when I do packet capture from both the phone side and PBX side I see request to register from the phone and PBX respond with authentication required.
If I'm not wrong the conversation seem to be looping around authentication request from the phone and authentication required from the pbx, not sure what's blocking the phone from authenticating to the PBX.

last time, I checked sbc logs and saw some error pointing to dns count resolve...if that could point to a problem. Checked again this time and I'm seeing "secure tunnel failed,secure tunnel is not supported by peer (negotiation timeout)"

Fews years ago used to experience dns issue withSBC and will edit config file and replace pbx domain with it's IP and this will start to work fine. Not sure it's still applicable nor it could be related to this case

 

[NickD_3CX]

The conversation is not looping at all, if the phone is in Factory Default state and cannot download the configuration, where did it get the settings to even try to send REGISTER requests.

This is a weird one, and personally I think it might be best to contact a 3CX Partner to help you with this deployment.
At this point, the only thing I suggest is to scrap everything and start over, delete the SBC in the PBX, format/uninstall the SBC, Factory Reset the phone(s) again, then start again.

First make sure that the SBC is installed correctly and shows as green/online:
https://www.3cx.com/docs/3cx-tunnel-session-border-controller/

After Factory Reset of the phone, try to re-provision as per the guide:
https://www.3cx.com/sip-phones/yealink-t4-series/