I started a game with only bots, then tried to resign. After being stuck in some kind of loading screen for a minute, I closed the browser tab.
Now, whenever I go to dominion.games and login, it tried to reconnect me to that game. pressing the "Cancel and Resign" button makes the loading screen briefly disappear, so I can temporarily see the regular menu, before coming back.
I tried deleting my browser cache and search for cookies(none found).
The "Spinning Castle" problem rarely occurs for not really clear reasons.
In order to get out of the Spinning Castle problem, you need to open a private(Firefox) or incognito (Chrome) window , go to dominion.games, enter your Name and Password, but don't click "Login". Instead, click on "Kick and Resign" (small font below the "Sign Up" button). Then you should be able to login normally (no need for private/incognito tab).
Ok, I seem to be out of it now.
Thanks!