Firmware for the H168N is highly region-specific. Using the wrong file your device.
button in the "Check New Version" section to see if an official fix is available. zxhn h168n v22 firmware update download fix
If you have downloaded a firmware file from an official source (like ZTE Support ), follow these steps: i24v2.0 Firmware - Tenda Global(English) Firmware for the H168N is highly region-specific