Error Codes

Error code (code) indicates the processing result of API requests.

Success Response

Response Code	Description
`0`	Interface response successful

Important Note

code being 0 only means interface call succeeded, not transaction success. Transaction final status needs to be determined by transactionStatus.

Security Restriction Errors (S prefix)

Error Code	Description	Solution
`S01`	Invalid IP address	Check if merchant has configured IP whitelist and add calling server IP to whitelist
`S02`	Request timestamp deviation from server time too large	Sync client system time, ensure time difference within allowed range (±10 minutes)
`S03`	Signature verification failed	Check signature algorithm, key, and parameter order, confirm parameters involved in signature have not been modified
`S04`	Interface call frequency exceeded	Reduce call frequency, follow platform frequency limit rules
`S05`	Data decryption failed	Check code encryption logic or check if key settings are correct
`S06`	Insufficient permissions	Contact administrator to apply for permissions or check if permissions are correct
`S07`	TMK key does not exist or key expired	Re-obtain TMK
`S08`	Working key does not exist or key expired	Re-obtain working key
`S09`	Login session expired or not logged in	Log in again
`S10`	Request authentication failed	Check key settings or authentication algorithm calculation is correct
`S11`	Duplicate request	Use different X-Request-Id to initiate request again, or wait 10 minutes before retrying

Client Errors (C prefix)

Error Code	Description	Solution
`C01`	Request parameter missing	Ensure all required parameters are provided
`C02`	Request JSON format error	Check JSON structure, bracket matching, and data type validity
`C03`	Merchant does not exist or is disabled	Check if merchant ID is correct and confirm merchant status
`C04`	Store does not exist or is disabled	Check if store ID is correct and confirm store status
`C05`	Device does not exist	Check if device SN is correct and confirm the merchant or store bound to the device is correct
`C06`	Duplicate request serial number	Ensure uniqueness of merchant request number, avoid duplicate submission
`C07`	Duplicate merchant order number	Ensure uniqueness of merchant order number to avoid duplicate submission
`C08`	Transaction locked (prevent concurrent operations)	Wait for current operation to complete before initiating new request, recommend business layer locking control
`C09`	Order unpaid	Check if order number is correct and confirm order status
`C10`	Order already paid	Confirm order status through order query interface, no need to repeat operation
`C11`	Order closed	Create a new order and initiate the request again
`C12`	Order does not exist	Check if order number is correct and order’s merchant
`C13`	Pricing currency not supported	Check merchant-supported pricing currencies and ensure request currency is in the allowed list
`C14`	Transaction amount exceeds allowed range	Check platform’s amount limit rules for this merchant/payment method, adjust request amount
`C15`	Refund amount exceeds original order amount or refundable balance	Verify original order amount and refunded amount, ensure total refund amount does not exceed refundable limit
`C16`	Request parameter is empty	Ensure non-empty parameters are set with correct values
`C17`	Request parameter format error or non-compliant with API specification	Ensure all values are filled according to documentation specifications
`C18`	Requested API endpoint does not exist	Check API endpoint URL
`C19`	Unsupported HTTP method	Check API HTTP method
`C20`	Device does not exist	Complete device activation or bind the device on the platform
`C21`	Security configuration missing or not found	Complete configuration
`C22`	Merchant is not authorized to access this application	Check configuration and request parameters
`C23`	Terminal does not match merchant	Check the merchant associated with the terminal
`C24`	Original transaction status not allowed	Check transaction status
`C25`	Transaction type not allowed	Check transaction type
`C26`	There are transactions currently being processed	Retry later
`C27`	Terminal transaction concurrency	Retry later
`C28`	No transactions in the current batch are eligible for settlement	Please call Batch Query first to check pending settlement transactions before requesting Batch Close

Merchant Configuration Errors (M prefix)

Error Code	Description	Solution
`M01`	Interface call permission insufficient or not activated	Apply for corresponding interface permission or renew
`M02`	Application does not exist or unavailable	Check if appId is correct and confirm application status on open platform
`M03`	Application and merchant binding relationship does not match	Confirm the application has been correctly authorized to the merchant and use the correct pairing information
`M04`	Merchant has not activated this payment product or payment parameters not configured or configured incorrectly	Confirm merchant has activated corresponding payment product, complete payment parameter configuration
`M05`	Failed to push message to terminal	Configure Taplink connection mode of terminal to Cloud

System Errors (E prefix)

Error Code	Description	Solution
`E01`	System busy, please try again later	Call order query interface to confirm transaction status, if unpaid order can retry
`E02`	Network timeout or error	Call order query interface to confirm transaction status, if unpaid order can retry
`E03`	Unknown exception	Call order query interface to confirm transaction status, if unpaid order can retry

Error Handling Recommendations

When encountering E01, E02, E03 errors, should first call order query interface to confirm transaction status
If order is unpaid, can retry; if multiple attempts still fail, contact technical support
When encountering C08, C26, C27 and other concurrency-related errors, recommend retrying later