Update: It doesn't appear to be an issue with my account on Factorio.com nor my ISP. I'm able to connect fine on my laptop (Win11).

I still get the problem on my PC (Win10), even when I turn off my Antivirus/firewall suite.

Does anyone have some suggestions I can use to pinpoint the problem?

I'm grateful for the suggestion but going offline then back online in the Steam client unfortunately didn't solve the issue. I was really hoping it would. I'm still having the problem. It definitely seems network or firewall-related but I get the same issue even when I completely disable my antiviru...

Initially, I had no problem connecting and downloading mods via the in-game connection to the mod portal. Then, in order to change the in-game display of my username, I logged into the factorio.com website and changed my username and password. Username was not updated in game, so I logged out of Fac...