Why did I get a late fee when I paid my rent on time?

Your lease requires you to pay your full balance no later than the 2^nd of the month. If you have other charges, such as a pet fee, Credit Contingency Fee, RBP Fee, etc., and you only pay the rent amount, then you will get a late fee for not paying your balance in full. Also, if you still had a remaining balance from the month prior, then your payment will be applied to that first, leaving your rent this month not paid in full, also causing a late fee. Basically, you always need to pay your full balance no later than the 2^nd of the month to avoid late fees.