Xfinity appears to be blocking port-forwarded traffic?

I recently made a game server that consists of a login server (port 6000) and a game server (port 8000). I enabled Port Forwarding on the Xfinity app and provided a couple of my close friends with the public IP of my network so that they could run the game client from their computer and connect to my server, which resides on my network behind the Xfinity gateway. 

For two days, my friends were able to connect to my server and play the game. I, too, was able to play after configuring the game with my public IP after setting all of this up. However, today I received an SMS message from a friend that the server was down, but it was not. It appears that Xfinity started blocking all of the traffic (tested with https://canyouseeme.org/).

How can I ensure that;

1. Xfinity confirms that they are indeed blocking traffic into my network that should be being forwarded to my server?

2. Xfinity stops blocking this traffic in the future?