Cannot call from CTI client to Yealink T21P E2

[InfoLS]

We are facing the issue that we cannot make a call from 3CX MyPhone in CTI mode. The HTTP-request is being sent to the phone (according to TCPVIEW.exe), but the call is not placed. Also, when attempting a call via the CTI mode, the web interface of the phone "locks up" and I get an HTTP-403 (not authorized) message. However, when calling directly from the phone is is visible in the 3CX MyPhone Client.

I've already disabled the anti-virus and firewall, but that didn't resolve the issue. I've also tried using another workstation, but that gives the same result. When using the 3CX WebClient this actually works.

Does anybody have an idea what's the cause of this? It used to work, until a few days ago.

 

[JohnS_3CX]

Hello,

Please provide some additional info about your setup (see here: https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/ )

Also please tell us if you are using Hot Desking on this phone.

 

[InfoLS]

Please find additional information below:

• 3CX Version,
  • Professional Perpetual 16.0.2.910
• Server OS
  • Windows Server 2012 R2 Standard
• Is the 3CX Server Hosted and where?
  • On premises
• IP Phone Make/Model/Firmware
  • Yealink SIP-T21P E21, firmware 52.84.0.15
• Provisioning Method: Local / VPN / STUN / SBC
  • Local
• Trunk Provider or Gateway Make/Model
  • Solcon, manually configured
• Has the Firewall Checker passed: YES / NO3
  • Yes
• Are custom Phone Templates being used: YES / NO
  • Not for this phone

We are not using hotdesking.

 

[JohnS_3CX]

Thanks,

And can you also tell me how you send the CTI commands?

3CX Windows client for example? (and what version)

Or are you sending them from another source? (please state it in this case)

 

[InfoLS]

Hello,

We are using 3CX MyPhone v16.0.1.81 to send the command. We look for a phone number in the company phonebook and click on this number to call. Oddly the 3CX web client works fine this way.

 

[JohnS_3CX]

Do you mean the 3CX Windows app? https://www.3cx.com/user-manual/

Does it show that CTI is enabled like this example?



The webclient does not use CTI, it sends SIP messages to the phone so it's normal in under certain conditions to see it work with webclient but not with the desktop client.

There are some requirements to make CTI work:

1. Regenerate the extension password using the button in the management console (for compliance)
2. Reset and reprovision your phone automatically via the management console (to inherit compliant passwords)
3. Send a new welcome email to the desktop client (so it will receive all the right credentials too)
4. Do not change anything in the extension or phone UI, leave it as the PBX provisioned it
5. Ensure the PC can see the web interface of the phone, using the local IP on the same subnet.

Once conditions are met it should work correctly, and it will not longer say you are not authorized when logging on to the UI. If the phone has blocked your PC's IP it will not listen to any CTI commands you send it.

 

[InfoLS]

Thanks for your help, it works! Strange that this client suddenly stopped working, but it works now so we are happy.

 

[JohnS_3CX]

Glad to hear! Did you perform any actions though?