Getting "The lobby server connection has encountered an error" number 2002, EU server

[Leocorr]

This started happening today. When trying to connect to Light or Chaos data centers (AKA the European ones), I get this screen:
https://imgur.com/Qz0N4Do

No buttons, no characters, no nothing... And a few seconds later, I get the error in the post's title. I press OK, and FFXIV closes.

NA data centers work fine.

I tried restarting my router, restarting my PC, and turning off my antivirus and firewall; nothing helped.

Any advice?

EDIT: Just tried running FFXIV on my laptop, while connecting my Wifi to my sister's phone's Hotspot, instead of my actual internet. And lo and behold... It works.
So does that mean there's some sort of issue with my internet...? What can I do to fix it? :C