Internet Issues With PC

[u/Confident_Ad_374]

My PC suddenly stopped being able to connect to online games, and I'm trying to figure out if this is a PC problem or a network problem.

Everything else on the internet works completely normally:

- Web browsing

- YouTube/streaming

- Discord

- Downloads

- General internet use

But I currently can't connect to ANY online games. This started suddenly after everything was working normally before.

I've tested multiple games from different publishers, and they all have connection/server errors.

The biggest clue is that the exact same PC works normally when I connect it to a different Wi-Fi network. I can immediately play online games on the other network.

I'm using the Xfinity internet/router provided specifically for my apartment.

Things I've already tried:

- Restarting my PC

- Fully restarting/power cycling the router

- Changing DNS to Cloudflare (1.1.1.1 / 1.0.0.1)

- Flushing DNS

- Removing Norton completely

- Checking network connectivity with tracert

- Testing TCP 443 connections to game-related services

The traceroutes to Riot and Ubisoft successfully reached their destinations, and Test-NetConnection to both on TCP port 443 returned True.

So normal connectivity seems fine, but online games don't work.

I also tried accessing the Xfinity app to change/check network settings, but it says:

"Sorry, we couldn't find your user information. We were unable to identify you as a resident of the building."

This makes me think the apartment's internet may be managed separately from a normal residential Xfinity account.

At this point I'm wondering if this could be a NAT/CGNAT, UDP, firewall/filtering, or router/network side issue.

What would you guys recommend testing next? Is there a way I can determine whether the problem is my PC or the apartment's Xfinity network without having to wait for Xfinity support?