Some websites not working just on one computer

Hello,

For about a month now certain websites haven't been working on my computer. Every other device on the network works fine, including my phone even when it's in the same place, so it's not a router issue. It's not a browser issue, either, because the effect is the same on Chrome (default), Firefox, IE, and Edge.
The sites that don't work are Netflix, Facebook, Spotify, and a couple of others. They will load initially but not stream. Torrents work fine, as does YouTube and Steam, so it's not a bandwidth thing. Running speedtests show that my connection fails at the upload segment every time.
I have changed my DNS, reinstalled drivers, turned off all the antivirus software I could find (to my knowledge just Defender, I uninstalled Avast), run a couple of virus checks, run CCleaner, searched for any weird programs, etc.
It's just my computer's interaction with this network, somehow, because on other networks all of those sites work, and upload tests work fine. I've disconnected and reconnected, obviously, and reset my router.
If anyone has any insight that would be great! Basically all I've figured out so far is that something is preventing my computer from uploading to this specific network - but I don't know what it is.

Cheers