Once you have created your account, you can log in at https://lagunita.stanford.edu/login. Enter your email address (not your username!) and your password, then click the green Login button. You can select the "Remember me" checkbox if you want to remain logged in on the site – this is not recommended if you are using a public or shared computer.
After five failed login attempts, you will be locked out of your account for about fifteen minutes, and this error message will be displayed:
This is a security measure intended to prevent unauthorized access to your account. If you are having trouble remembering your password, it is better to click the "Forgot password?" link and reset it than to keep guessing. Note that if you reset your password while locked out, you will still have to wait fifteen minutes for your account to be unlocked.
If fifteen minutes have passed and you are still seeing the lockout message, try clearing your cache and cookies, then closing and reopening your browser.