Port Forward issue Xfinity Gateway

Hi,

referring to this official Xfinity document - https://www.xfinity.com/support/articles/port-forwarding-xfinity-wireless-gateway

I am trying to configure Port Forwarding for the device connected to my Xfinity Gateway modem via Lan port using an ethernet cable.

The above document clearly says that we can make this from Xfinity Gateway using the admin web tool instead using a mobile app.

• Go to http://10.0.0.1 using a device that is connected to your network.
• Log in to the Admin Tool:
  • Username: admin
  • Password: password
  • Note: You will be prompted to change your password the first time you access it. Please change the password and if required login to the admin tool with the new password.
• Select the Advanced menu in the left pane, then click Port Forwarding.
• Select Enable. The button will turn green.

But why????????  There is no option to enable this? instead of there is a message that we should use a mobile app.

"Managing your home network settings is now easier than ever.
Visit xfinity.com/myxfi to set up port forwards, among many other features and settings."

ok, I did try using the mobile app. But this mobile app can manage only devices which connected via wifi, not plan.  "Xfinity Mobile APP doesn't support the Port Forwarding option for devices that connects via LAN port.

Why you disabled this option from Xfinity Gateway? Why do we have to use the mobile app?

How we can make this enable from the Xfinity Gateway??? Tell me, please refer to this document where is the enable option for this? - https://www.xfinity.com/support/articles/port-forwarding-xfinity-wireless-gateway

And when we go the link which we see from screenshot, it clearly says that we can manage only WIFI network not LAN connected.