Powering down a phone by pulling the plug isn't always the best way to get a resolution and its always best to try a soft boot first.
If you are requested to do a reboot on your phone then please follow this guide,
This How-to: Guide will show you how to soft boot your Yealink phone.
Yealink T21P phone.
- Locate the X (or cancel) key.
- Press and hold the X key until you see a prompt on the screen.
- Press the OK soft key (below the screen) to confirm the reboot.
- Wait for the reboot to complete.
- Your phone may update its configuration after the reboot which may result in a second reboot process automatically within a minute or two of the first reboot.
