Port forwarding for wired ethernet device

I saw this problem reported in a number of posts, I was able to solve it by assigning a "fixed" IP address to my server box which does not have wireless.

Steps to do this

1. Configure your server to use DHCP to acquire an IP address and to always connect for all users
2. Connect your server with an ethernet cable to the Xfinity gateway or the ethernet connection on a pod
3. Determine the IP address that was assigned to your server and the MAC address
4. Log in to your Xfinity gateway at 10.0.0.1
5. Click on "Connected Devices"
6. Click on "Add Device with Reserved IP" at the bottom of the list of devices
7. Enter the name for the device, the MAC address, and the IP address it was assigned above
8. Click "Save" and log out from the Xfinity gateway
9. Reboot your server
10. Open the Xfinity app on your phone
11. You will now see your server in the "Connected Devices" section
12. Click on "View WiFi Equipment"
13. Click on "Advanced Settings"
14. Click on "Port Forwarding"
15. Click on "Add Port Forward"
16. Now you can select your server and set up port forwarding

You may have to restart your router and app too to get the new server to show up, but keep at it and you'll find it there eventually !