The software will lockout a user after five failed attempts to sign in. After five failed attempts, your username will be locked for 5-minutes and an alert will be sent to the email associated with your username. You will be able to make further attempts to log in after the 5 minutes have passed.
Login Screen Message
After five failed attempts, you will see a message that your user account has been locked.
An email will also be sent after five failed attempts indicating that you can try again in five minutes or reset your password to unlock it immediately, set up a new password, and try again. To reset your password the "Forgot Your Password" article walks through those steps.
If you did not try to log in to the software, then someone may be trying to sign in with your username and should be a security concern.