DO NOT do this unless you have specifically been advised to. This will render your phone inoperable until the reconfiguration is completed. This is NOT a normal basic troubleshooting step.
This applies to current Grandstream models such as the GXP2130, GXP2135, GXP2140, GXP2160, and GXP2170.
If you are setting up a brand new phone out of the box, you can usually skip the factory reset section. If there is any chance the phone was previously configured, you must do the reset.
On the phone, press the center button in the five-button navigation keys to bring up the menu. Scroll to the right of the screen then keep pressing the right-arrow button until the next screen comes up. Select the "System" option. Press the up arrow once, which will take you to "Factory Reset" and press the "Select" softkey. Confirm by pressing the "Yes" softkey. The phone will clear its memory and reboot, which can take a few minutes.
After the phone reboots, it may take 1-5 minutes for this prompt to show up. The phone will ask you to enter the extension number and voicemail password (PIN) for this phone/extension. This is a one-time task, and the phone will remember this permanently. If you do not have the voicemail PIN for the phone, please contact us for it.
It can be tricky to enter the numbers, so please watch the screen prompts carefully. In particular, if there are two duplicate numbers in sequence, you need to wait for the prompt to change.