I have an infuriating issue that I've been troubleshooting for some time now, has been happening for the last few weeks (just moved into my girlfriend's house and it has only happened there, no issues beforehand with the same PC)
I am on an ethernet connection, using an Arris SBG6900-AC as a modem/router. The connection is fine, and speed is good (400Mb), but for some reason, connecting to anything that uses UDP (at least that is my hypothesis) does not work at all, things like Slack, Discord, Spotify, game clients, etc. hang and act as if there is no connection at all. However, visiting websites works completely fine.
Occasionally, with discord, I can get it to launch, but trying to join a room or a call is met with a perpetual RTC Connection -> No Route loop, and it never successfully connects.
If I turn on my PIA VPN in TCP-only mode, everything magically works completely fine (it fails to connect using UDP), which is part of what leads me to believe this is a UDP issue. I spoke to my service provider earlier today, and they said everything looks normal on their end connection-wise, but there wasn't much they could help with beyond that as we aren't using their hardware.
Looking to see if anyone has had similar issues or might know a way to further investigate. I am running Windows 10, have reset/reinstalled drivers for all network adapters, turned off Windows firewall, and still am experiencing the issue.
I have tried switching to Wifi on my desktop as well, but its spotty and disconnects often . . . trying to focus on one issue at a time.
Perhaps its worth going to my service provider and trying their hardware?