PAYM-1af31b

The payment was rejected because it looks like a duplicate of a recent payment. Returned as HTTP 400.

Why you're seeing this

Shopmonkey detected a payment closely matching one submitted moments earlier and blocked it to prevent double-charging.

How to resolve

1. Check whether the earlier payment already succeeded before retrying.
2. Avoid resubmitting identical payment requests. If you retry automatically, wait and confirm the prior result first.