TK: A delinquent or derogatory item is the worst status on your reported accounts.
Your credit file is showing an account with a payment that was at least 30 days late and/or on which a lender has reported a derogatory status. Late payments are a proven indicator of increased risk. People with late payments are at risk of being overextended, putting existing credit with lenders at risk.
Paying bills on time every month is important to maintaining a good credit score. If you remain behind with any payments, bring them current as soon as possible, and then make future payments on time. Over time, this will have a positive impact on your score.