Below are the common error messages returned and their respective descriptions:

Duplicate reference number - Do not reuse the Reference Number of a previous successful payment transaction.

Invalid merchant code - The merchant code does not exist.

Invalid parameters - Some parameters passed to iPay88 are invalid or empty.

Overlimit per transaction - You exceeded the amount per transaction that is assigned to merchant's account.

Payment not allowed - The Payment method you requested is not allowed for the merchant's account.

Permission not allow - Please, ensure the Referer URL is the same as the one registered with iPay88.

Status not approved - Merchants account was suspended or not active.