GENERAL TROUBLESHOOTING- START HERE
Many issues can be solved by simply rebooting your device or verifying power and network connectivity. Remember, if there's no Internet your phones won't work.
- Verify power. If your device uses Power Over Ethernet (PoE) you will likely only have a single network cable attached. Make sure this is plugged in tightly and connected at both ends. You may have to trace this cable all the way back to your network switch or router and ensure there is a light on the switch port. If you're using a power brick, make sure it's plugged in. However it's connected, disconnect the power source and connect it again to reboot.
- Verify Network Connectivity. Ensure the Ethernet cord is plugged in on the device and in the wall. Unplug it and plug it back in.
- Ensure all the cords are plugged into the correct port on the back of the device. See pictures to confirm its plugged in correctly.
Yealink Phones: Click for advanced troubleshooting
Panasonic TGP600: Click for advanced troubleshooting
Grandstream ATA: Click for advanced troubleshooting
Polycom Phones: Click for advanced troubleshooting