If you are able to access the web interface you can reset it by pressing the "Perform Reset" button Which is under The System -> Backup / Flash Firmware tab.
Or if you are able to get ssh access you can reset it using this command "rm -r /overlay/*" and then "reboot".
If you can't access your miner over the network you can reset it using the reset button on the control card.
First make sure you miner has been powered up for at least 2 minutes. Next with a paperclip or other tool that will fit in the reset slot hold down the reset button for 10 seconds and then release.
Wait for two minutes and then power cycle your miner. After it boots back up it should be accessible on the ip address 192.168.1.99.