Perhaps most common reason that you cannot access Sniffie is that you type in the wrong email or password. In this case Sniffie service is notifies you with a message about incorrect credentials above the email field.
This means either your password or your username (email) are typed incorrectly. If you try and fail to login 5 or mote times within 5 minutes, your account will be locked for security reasons for the next 5 minutes, and an email is sent your account’s email address notifying of a possible brute-force attempt. Two-factor login is also enabled for the account at that time. After 5 minutes you can try login again.
If you have forgotten your password, request a new password.