An identical EFT allocation was created on this policy in the last 10 seconds: the same amount, payment_date, payment_method_id and description. premium_type is not compared. No payment is created. The error message names the existing payment. To allocate two identical amounts on purpose, use a different description. A 409 on a retry after a failed request means the first payment was created; the proof of payment sent with the retry is not stored.