IA: You have too many recently opened installment accounts.
An installment account is one with a fixed monthly payment for the life of the loan. Auto loans and student loans are common examples of installment loans. Because too many of your installment accounts were opened recently, the history on those new accounts is not long enough to provide sufficient payment and account history to demonstrate responsible behavior on those accounts. In addition, having multiple accounts that are relatively new is seen as a higher risk because of the possibility of becoming overextended, which can then lead to late payments or defaulting on the account.
Use your existing credit responsibly and make your payments on time. Your credit score will benefit as you make payments on time and manage the accounts in a responsible fashion. Manage your credit wisely by planning ahead for your credit needs and avoid applying for more credit than you need.