Can't Connect to Steam Servers

[yomi ♡]

For some reason, I can't connect to steam servers on one account, but on the other it's perfectly fine.

I've contacted steam support who has given me a standard reply answer without looking into my account that it has to do with my "connectivity", however it clearly works with a new account and not my old account, meaning my steam account is forever unable to connect to steam servers.

I know it's an issue with only this account because I've tried other accounts. This only is an issue for me on one game, and results in me not being able to use a DLC I've purchased.

Is there any fix for this?


Things I've tried:
- reinstalling said game
- going offline and online on steam
- rebooting pc, rebooting steam
- switching my only firewall (windows)
- using a newly made account (clearly works and connected in less than a second)

Thank you for reading.