STUN problem with router

[Albert464]

Hi, a customer has always used a telephone connected in STUN to his modem, it has always worked. This morning (without connecting other devices and without doing anything) the word "No service" appeared.

Telephone: Yealink T42S

The phone in the router's dashboard appears. On the switchboard dashboard no.
If the phone connects to another router it works.

What can it be?

 

[Saqqara]

Disabled SIP-ALG on the router, it may have done a firmware update.

Also check to see if you can see anything to do with SIP and switch it off.

 

[Albert464]

The router has no SIP-ALG function. The switchboard is in the Cloud, only the phones are in the customer's office.

 

[leejor]

Was the IP blacklisted in 3CX? Check the 3CX Activity Log to see if there is a (failed) registration attempt when the set is powered up.

 

[cobaltit]

And you've forwarded the ports as required? And it's the only phone behind the router?

 

[vectra]

Try to replace local IP address. In some reasons I had this situation many times. When you change local IP of IP phone it will register immediately.