I had this problem already and I can’t remember what I did to fix it. I think I used my phone as a wifi tether and connected via that and it allowed me, but it’s not working this time - I have a VPN and have tried with/without it, changing location, settings etc. I just have the box with spinning logo.
Seems to be a huge common problem when you google this… how has it not been fixed yet? the amount of money lost from people who gave up trying etc.
I’ve tried every solution I can find posted.
Edit: My issue was that I was using junctioned folders for the Battle.net and Blizzard Entertainment directories in local data, removed the junctions (symlinks) and let it use the local data normally and it works. Seems to have some issue with that for some reason.