Was it working before? What happened?
Are you able to access the WebUI of the device? If so, could you please attach a troubleshoot file to your question? Troubleshoot file can be downloaded from System -> Administration -> Troubleshoot.
In case you cannot access the WebUI, please, try to reset the device to factory settings. If this does not help, please reinstall the firmware via bootloader procedure. The instructions are available here.
Let me know if you were able to reinstall the firmware via bootloader or not. Thanks.