Issue: The screen on a GXP21x0 displays a "Connection Failed" message, but the phone is still able to make and receive calls.
Grandstream handsets have two built-in applications, Weather and Currency, which are cycled through by pressing the first (left-most) Soft Key.
Unfortunately the Weather application does not currently work and instead displays a large "Connection Failed" message on the screen. This is due to be fixed in the next version of the phone firmware.
If your Grandstream handset is displaying a large "Connection Failed" message, press the first (left-most) Soft Key to cycle to the Currency application. Pressing it a second time will cycle back to the home screen of the phone.