@Kevin Kho My account had only one Team, where I was the only user on it. I deleted this Team yesterday (since I was not using it anymore) to join in another one, and I believe this led to the issue. I had asked someone to invite me to their team, and now I'm able to log in.
I think that would be good in the future to show a warning that this would lead to an error or that it's not possible to use the Cloud without being in at least one team (I don't know if this already exists on docs). Thank you!