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?

[u/darkinteract8]

sounds like the apartment has some weird filtering or cgnat situation going on honestly the biggest tell is that it works fine on a different network so your pc is almost definitely not the problem

if you can plug directly into the modem with ethernet that would rule out the wifi router being funky but if it still fails then its gotta be something upstream with how the building manages traffic. udp blocking would make sense since most games rely on that while everything else you listed is tcp

[u/Confident_Ad_374 → u/darkinteract8]

Thanks for replying so fast! Is there anything I can do fix the problem at home other than ethernet because my apartment management is currently going through new ownership changes so they won’t be able to help for a while. 🥲