The behaviour of the Hub is pretty weird when it comes to signing in. When I launch it, I'm often signed off but it I don't bother and just use it, it appears that the situation changes and I end up being logged in. It seems that the Hub takes its time updating the account state. Next time, don't click on "Sign in" and see if it changes by itself in time.
Still not being able to log in Unity Hub 1.4.0. Also, the 2018.3 version is not appearing on the Official Releases tab.
Sounds like it's not getting access to the internet. You on a managed network that maybe added some firewall rules without you realizing? Also, post the logs here for more help... Log locations: Windows: %UserProfile%\AppData\Roaming\UnityHub\logs Mac: ~/Library/Application support/UnityHub/logs Lastly, maybe try the ye-olde reboot your machine approach.
I've had sign-in issues before, make sure to close hub in the task manager after starting a project and resign-in. Sometimes that fixes it. Lately I've had more sign-in issues with 1.4.0. I can watch videos fine on youtube, but stay signed in? Nope. Sometimes I'm lucky though. It's especially bad with collab. It seems to work fine downloading from the unity store, but add collab and oof. I'm on a team that uses collab and man, talk about sign-in issues. You don't realilze what a problem it is until you work on a project without collab and realize how much faster and pain free it is.
Ah, I think it's our network, I've been hading several doors blocked and I think that Unity sign in is one of them. Everything is working fine on my PC at home so I suppose that this might be the problem. Thanks for the replies everyone! Btw, rebooting and killing the task didn't solve it...
Well... firewall issues != Unity QA problem. Although, they could do more proactive, automated connectivity testing and pop up a helpful dialog, like "hey, we can resolve http port 80 but not http port <xyz> -- check your firewall settings and/or contact your network admin"