Make sure you have this webpage up and kept up and logged in while you play in-game otherwise it won't work!
https://feral-heart.com/login/index.php
^^^
If that doesn't do the trick what's happening when you say "it won't let me log in" exactly? That way we can all help you better!
You could always try reinstalling chrome or just stick to using your phone, because honestly. The play game log in has been giving staff trouble for the past few months, so lets hope they fix it. Because it is something they can fix. Also if you are banned it tends to also do this as well, so if so. Continue to take it up with a mod or an admin please.