Yealink T42S handsets provision successfully but fail to register

[irpete]

Hi team,

I've just configured a new 3CX Free instance and have successfully provisioned and registered a single T53W router phone. I can provision 2 T42S handsets (with 66.86.0.180 firmware) via the router phone but they fail to register. I'm able to log into the 3CX instance from the site IP address, so we're not blacklisted. I've removed a T42S and re-provisioned it, but it still fails to register.

One thing I suspect is that all handsets were previously registered to a 3CX 4SC server, but I removed them before re-provisioning. I've also rebooted the old 3CX server in case any registrations were still active.

If I log into the T42S handsets using the 3CX web console credentials, I can confirm all registration information is intact. I'm at a loss.

Any ideas?

 

[irpete]

A quick update this morning. The event log contained a new message that wasn't shown overnight:

SIP request (REGISTER) from [site WAN IP] was rejected. Reason: Block WAN requests is ON.

Before I saw this message, I had logged a ticket with Yealink to remove the handsets from RPS, and after I did that both handsets lost their account information. I reset them to factory but they still didn't auto-provision. After I entered the provisioning URL, they both come online again and successfully registered. I changed no other settings

I have no idea whether the Yealink RPS removal request was co-incidental, or if a 3CX support member whitelisted the IP address and allowed registration. Either way, problem solved.