Provisioning the phone: Network checking fails

[vgarg]

I updated firmware on T21P E2, when rebooted it asked for user name. I entered extension 302 as per instructions. then message came network checking and user name screen still there. not able to move forward from here. any help will be appreciated.Thanks

 

[JohnS_3CX]

Is this a phone that was already provisioned and working?

Or is this the first time you are connecting it to a 3CX system?

 

[vgarg]

No it is new phone, i factory reset it, updated firmware, config files loaded successfully, it does prompt username, which i put the extension number 302, it does not go tp password screen like it unable to contact hosted 3cx instance. i will try sbc method soon as recommended, are there any ports need to be opened in firewall, if yes to what ip range. thanks a lot.

 

[JohnS_3CX]

The SBC does not require any port forwarding at all at the site where you install it.
It is designed to work well behind firewalls and NAT.

If you had already forwarded any ports for individual Yealink phones, you can remove the forwards as they will no longer be needed when you switch phones to use SBC.