It doesn't meet the installment conditions: banks have certain requirements for installment repayment, such as credit limit, consumption amount and bill type. If these conditions are not met, you may not be able to apply for installment.

overdue or bad credit: if the credit card has an overdue record or bad credit, the bank may restrict the use of installment repayment.

limit: the available credit card limit may not be enough to support installment repayment, or it has reached the upper limit of installment limit.

bank policy change: the bank may have adjusted the installment repayment policy, which makes it temporarily impossible to installment.

special consumption items: some consumption items may not be allowed to be phased, such as cash withdrawal, handling fees, late fees, etc.

time limit for application: the bank may have a time limit for installment application, and it may not be able to apply for installment after the specified time.