Also, check out:
How do I unlock my Company Admin user?
If you have 5 consecutive failed login attempts with your Company Admin user, your account will become locked. To unlock your user, please follow the instructions below.
PLEASE NOTE: You can also have any other Company Admin within your profile unlock your user for you.
STEP 1. Inside the Admin Console, attempt to log in. When the Unlock User link appears, click on it.
You'll receive a message informing you which email address the unlock email has been sent to.
STEP 2. Open the email sent from email@example.com.
STEP 3. Click the link provided to unlock your user.
You will be automatically redirected to the Admin Portal where your user is now unlocked.