login problems have a number of causes. here are a few common fixes that should get things working.
make sure you're using the right email address
is the email address you're trying to log in with definitely the one you used to register with us? before trying anything else, double-check this.
try resetting your password
check for password manager issues
are you using a password manager? if so, ensure that it is not auto-filling with an old or incorrect password. turning the password manager off or using a private/incognito browser window are good ways of checking this.
clear your browser cache