If you have tried to sign into your account too many times? You maybe timed out from signing in!
If you attempt to sign into a Google Apps account incorrectly several times Google will add a timeout on your account before you can sign in again to prevent possible brute force attacks on your mailbox. This timeout period can last up to 20 minutes.
Note: If you are timed out, you will be presented with a Captcha challenge when you attempt to sign into Google Apps (example below)
If you know your password is correct (or have recently changed it to get access to your mail) you may want to skip the timeout period and get directly back into your Email.
In order to do so, navigate to the website: https://www.google.com/a/u.brockport.edu/UnlockCaptcha and enter your username