Updated
Quick fix
“Unregistered” means the phone can’t sign in to your phone service. Restart the phone, confirm the internet works, and restart the router. If several phones show it at once, the internet connection or router is the likely cause.
Every VoIP phone signs in (registers) to your phone service so it can make and receive calls. When it can’t, you’ll usually see a warning on the screen and calls won’t ring.
Step by step
Is it one phone or all of them?
If every phone is unregistered, look at the internet connection, router or firewall first. If it’s one phone, focus on that phone, its cable and its port.
Restart the phone
Unplug the power or PoE network cable, wait 10 seconds and plug it back in.
Check the internet and router
Make sure websites load, then restart the modem and router. After the router is back up, restart the phones.
Think about recent changes
A new router, firewall, internet provider or network settings change is a common cause. Some routers have a feature called SIP ALG that can interfere with VoIP; many VoIP providers recommend turning it off. Ask your IT team or provider before changing router settings.
Don’t factory-reset without checking
A factory reset can erase the phone’s settings. Contact your provider first; many phones re-download their settings automatically, but not all.
Contact support
Tell us the phone model, what the screen says and when it started.