SBC Phone not registering

[Alphabetic]

18.0 U8

Hi

i've got 3 Yealink T53W running 96.86.074 all set up as SBC phones, working fine before we shipped them.

They're onsite now and 2 of the 3 were online, the other was not.

I had an entry in the event log to state this ext had been blocked.

SIP request (REGISTER) from x.x.x.x was rejected. Reason: Block WAN requests is ON.

I've removed the IP from the blacklist and went ahead and pushed the FW update for the other phones and now all of them are showing no service with the event log giving me

SIP request (REGISTER) from x.x.x.x was rejected. Reason: Block WAN requests is ON. for the same extension I intially had issues with.

 

[Alphabetic]

SIP request (REGISTER) from x.x.x.x was rejected. Reason: Block WAN requests is ON.

This is coming up on 1 extension in particular thats an SBC phone, same WAN IP as the other 2 - ext isnt disabled so not sure whats going on.

 

[Alphabetic]

Ok so FW to 76 from 70 resolved issue.

Weirdly though, this phone was initially set up in office on .70 and worked fine. Shipped to site and it didnt work..

 

[Alejandro_3CX]

Hi @kieferschild before provisioning an IP Phone, please validate that it is using the supported firmware as shown here

Furthermore, if this device will be using the tunnel connection, check that the extension does not have the parameter Block Remote Tunnel Connections enabled since it will block the tunnel connection when using the SBC.