My Gateway is not showing online in the Cloud.

The first things to verify are as follows: 
1. Are there lights on the Network plug on the back of the Gateway?
2. Be sure that IF you are using both network adapters that they are going to different switches (or VLAN's).
3. Make sure that the WAN network port is connected to a switch that has internet access, and DHCP.
4. If all the above seem good, the next step may be to reboot the system to ensure it detected everything properly. To do so momentarily press the front power button, it will begin it's power down procedure.  This will take around 2 full minutes to shut everything down. Once the lights and fans go off you can power it back on the same way.
5. If the restart does not solve the problem you may have a port issue.  Please see the following KB for details on that:  https://www.qumulex.com/kb/port-forwarding