Your gateway device (Mate3, Mate3S and/or AXS Port) uses the Internet to communicate with OpticsRE. At times, Internet connectivity can be lost - a reset router, Internet conditions, your Internet provider resets the line or any of a number of reasons. Your gateway is designed to automatically reconnect when the Internet connection is restored. While there is no connection, the OpticsRE dashboard will show that your gateway is "Offline", i.e., it cannot communicate with OpticsRE.
At times, this automatic reconnection fails. If you believe that the gateway's Internet connection should be up and functioning and yet the OpticsRE dashboard shows "Offline", you can attempt to have the gateway reconnect by power-cycling the gateway. You can do this by removing the CAT-5 cable from the gateway to the hub (or inverter, if no hub), waiting approximately 10 seconds and then plugging it back in. The gateway will restart and should then automatically reconnect.