Solved New 3CX Install Not Showing Phones

[technomojo]

I've just completed a fresh install of 16.0.619 (Pro Annual) on Windows 10 Pro, v2004, completely up-to-date.

I believe the firewall and port forwarding is configured correctly; the firewall check completes successfully.

However: no phones are appearing in the Phones list.

This site has Yealink T41P and T48S, all on latest FW updates as per the 3CX page (T41-36.83.0.130 and T4XS-66.85.0.5, respectively).

Another piece of background: Their unmanaged Netgear switch died recently, which we replaced with a Ubiquiti UniFi 24-port Managed PoE+ switch. No issues running 3CX with the same Yealink phones since (until today's fresh install). Could this switch be getting in the way of the initial detection?

Also, I'm having trouble convincing the SIP trunk to register, but that could be unrelated. This customer is still subscribed to a formerly-approved SIP provider (Internode, AU).

 

[FridayIT]

Is the network card for 3cx and the phones on the same subnet and vlan? (if applicable)
The unifi switch should work as we have some in production.

have you also confirmed the devices can talk (ping, or telnet etc. )

 

[Saqqara]

Do you have any 3rd party antivirus / firewall software running on the PC ?

As above, are the phones getting an IP address, can the PC ping the phones ?

 

[technomojo]

Thank you both for your replies.

Yes, the network card on the 3CX host PC and phones are on the same subnet (no vlans). Good to hear the Unifi switch works. I gather there were no clever default settings that needed to be disabled?

Yes, I can ping the Yealink handsets from the 3CX host PC no problem and log into the phones' web interfaces.

The 3CX host PC has Avast antivirus (with exceptions for 3CX program files/program data directories) and Windows firewall.

 

[Saqqara]

Disable Avast and see what happens after you factory reset a phone.

 

[technomojo]

What do you know... That worked!

I'd tried disabling Avast to see if the phones would populate in the list but no joy. So the trick is to factory reset while Avast is disabled...

Any idea why that works?

 

[Saqqara]

At at guess, Avast maybe blocking PnP traffic.

 

[technomojo]

Thanks for your help, much appreciated!

 

[YiannisH_3CX]

I would recommend removing Avast completely from the PBX machine as the machine should be a dedicated only for the PBX so an additional AV is not needed.
We have seen some very weird issues caused by AV software so it is better to remove it entirely.