What does Authentication Failed mean?
Authentication failed means there is a temporary block due to too many failed attempts. After 30 minutes after the last login attempt, the block is removed automatically by the system. You can also contact our Sync support team at help@sync.com to remove it for you.
If you have forgotten your password see:
https://www.sync.com/help/what-do-i-do-if-i-forget-my-password/