Deleting the file at this address helped me: C:\Windows\System32\drivers\etc

Specifically, the hosts.ICS file, and possibly also host.ICS (or something similar). There might be two of them. Just delete hosts and the previous one (it's essentially empty and the game might have been referencing it incorrectly). I hope this helps someone.

You can also check if your Ubisoft Launcher version matches the official website. I personally had to download it from their website because it didn't update automatically.