> ## Documentation Index > Fetch the complete documentation index at: https://waffo.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Error code quick reference > A complete list of Waffo API error codes and category descriptions. ## Error code format An error code consists of an alphabetic prefix + digits: | Prefix | Category | HTTP status code | | ---------- | ----------------------- | ---------------- | | **0** | Success | 200 | | **A**xxxxx | Merchant-related errors | 400-401 | | **B**xxxxx | User-related errors | 400 | | **C**xxxxx | System-related errors | 500-503 | | **D**xxxxx | Risk control rejection | 406 | | **E**xxxxx | Unknown errors | 500 | **Category E errors (unknown errors)**: Caused by an unknown state in Waffo’s internal systems or third-party systems. Merchants must continuously query the transaction status until a final success/failure result is returned. ## Full error code list ### Success | Error code | Description | HTTP | | ---------- | ----------- | ---- | | 0 | Success | 200 | ### A - Merchant-related errors | Error code | Description | HTTP | | ---------- | ----------------------------------------------------------------------------------------- | ---- | | A0001 | Invalid API secret key | 401 | | A0002 | Invalid signature | 401 | | A0003 | Parameter validation failed | 400 | | A0004 | Permission denied | 401 | | A0005 | Merchant limit exceeded | 400 | | A0006 | Abnormal merchant status | 400 | | A0007 | Unsupported transaction currency | 400 | | A0008 | Transaction limit exceeded / payment amount must be within the allowed range | 400 | | A0009 | Order does not exist | 400 | | A0010 | Merchant contract does not allow this operation | 400 | | A0011 | Idempotency parameter mismatch error | 400 | | A0012 | Insufficient merchant account balance | 400 | | A0013 | Payment has succeeded; the order cannot be canceled | 400 | | A0014 | Refund not allowed due to refund rules | 400 | | A0015 | Payment channel not supported; the order cannot be canceled | 400 | | A0016 | Payment channel rejected; the order cannot be canceled | 400 | | A0017 | Payment channel not supported; the order cannot be refunded | 400 | | A0018 | The user has no available payment method | 400 | | A0019 | Refund not allowed due to a chargeback dispute | 400 | | A0020 | Payment amount exceeds the transaction limit | 400 | | A0021 | Cumulative payment amount exceeds the daily transaction limit | 400 | | A0022 | Multiple products detected; the merchant must specify the product name | 400 | | A0023 | Token has expired; the order cannot be created | 400 | | A0024 | Exchange rate has expired; the order cannot be processed | 400 | | A0025 | Period number must be greater than one | 400 | | A0026 | The checkout page language specified by the merchant is not supported | 400 | | A0027 | The number of refunds has exceeded the maximum of 50 | 400 | | A0028 | The subscription is still in progress or has failed, so the management URL is unavailable | 400 | | A0029 | Invalid card data provided by the merchant | 400 | | A0030 | Unable to find the card BIN provided by the merchant | 400 | | A0031 | The card scheme or card type provided by the merchant is not supported | 400 | | A0032 | Invalid payment token data provided by the merchant | 400 | | A0033 | Multiple payment methods detected; the merchant must specify the payment method country | 400 | | A0034 | The order expiry time provided by the merchant has expired | 400 | | A0035 | The current order does not support capture | 400 | | A0036 | The current order status does not allow capture | 400 | | A0037 | The user payment token is invalid or has expired | 400 | | A0039 | The order has already been refunded by the chargeback alert service | 400 | | A0040 | The order cannot be created concurrently | 400 | | A0041 | Chargeback does not exist | 400 | | A0042 | Chargeback status is already final | 400 | | A0043 | The current status does not allow evidence submission | 400 | | A0044 | File does not exist | 400 | | A0045 | The MIT transaction cannot be processed because the tokenId status is unverified | 400 | | A0046 | Access denied: the request IP is not in the whitelist | 401 | ### B - User-related errors | Error code | Description | HTTP | | ---------- | --------------------------------------------------------------- | ---- | | B0001 | Abnormal user status | 400 | | B0002 | User limit exceeded | 400 | | B0003 | Insufficient user balance | 400 | | B0004 | The user did not complete the payment within the timeout period | 400 | | B0005 | User authorization failed | 400 | | B0006 | Invalid phone number | 400 | | B0007 | Invalid email format | 400 | | B0008 | Auth code is invalid | 400 | | B0009 | Auth code has expired | 400 | | B0010 | Auth code has been used | 400 | | B0011 | Access token is invalid | 400 | | B0012 | Access token has expired | 400 | | B0013 | Access token does not exist | 400 | ### C - System-related errors | Error code | Description | HTTP | | ---------- | -------------------------------------------------------- | ---- | | C0001 | System error | 500 | | C0002 | Invalid merchant contract | 500 | | C0003 | Invalid order status; unable to proceed to the next step | 500 | | C0004 | Order information mismatch error | 500 | | C0005 | Payment channel rejection | 503 | | C0006 | Payment channel error | 503 | | C0007 | Payment channel under maintenance | 503 | ### D - Risk control rejection | Error code | Description | HTTP | | ---------- | ---------------------- | ---- | | D0001 | Risk control rejection | 406 | | D0002 | Risk transaction limit | 406 | ### E - Unknown errors | Error code | Description | HTTP | | ---------- | -------------- | ---- | | E0001 | Unknown status | 500 |