Yealink Phones not provisioning

[sulli86]

Hello,

I have two clients now with 3cx hosted in Azure with SBC's on site. One is a brand new install and the second a install from a year ago.

I am having issues with auto provisioning. both sites will not work however the phones are discovered.
The phones in question are T46 and T42 I have confirmed with Yealink that the phones are not listed in RPS has anyone else got anything we can try or know of an issue

 

[Saqqara]

Do you have option 66 configured on the dhcp server on the sbc network, if so delete it

are you blocking https port out on the sbc network, https port is required to provision the phone

are you blocking ntp port out on the 3cx network, ntp port is required

are the phones running the latest firmware https://www.3cx.com/sip-phones/yealink-t4-series/#h.7ls0w5vyhlnd