clear config ubiquiti router

1. Overwrite the current start-up (config.boot) file with the default start-up file (config.boot.default).
You can backup config.boot to other file. like
sudo cp /opt/vyatta/etc/config/config.boot config.boot.backup
Then

sudo cp /opt/vyatta/etc/config.boot.default /config/config.boot

2. Reboot the EdgeRouter.

reboot
  Proceed with reboot? [confirm]

3. Wait for the reboot to complete.

4. Connect to the eth0 port and manage the device using the default IP address (192.168.1.1).