Error Codes

Error code	Cause of error
NO_SIGNATURE	The required signature in header X-Mplus-Signature is not present.
INVALID_SIGNATURE	The signature in header X-Mplus-Signature is invalid. Check your implementation of HMAC
INVALID_JSON	The JSON in the body is invalid JSON.
INVALID_DATA	The body is valid JSON, but the data in it is not valid. E.g. putting a string into a numeric field.
NO_SUBSCRIPTION_ID	The header X-Mplus-Subscription-Id is not present.
INVALID_SUBSCRIPTION_ID	The subscription ID in header X-Mplus-Subscription-Id is invalid.
NO_CONTENT_TYPE	The header Content-Type is not present.
INVALID_CONTENT_TYPE	The content type in header Content-Type is not one of the supported content
NO_EVENT_DETAILS	An expected object containing event details was not included with the request. E.g. the scanCode event call did not contain the scanCode object.
NO_SCANNED_CODE	The scanCode object did not contain a scannedCode.
LINE_ALREADY_HAS_DISCOUNT	The line you are trying to apply a discount to already has a discount.
INVALID_LINE_ID	You are trying to change or delete a line that does not exist in the session.
LINE_ID_ALREADY_EXISTS	The line you are trying to added has an ID that already exists in the session.
INVALID_RELATION_NUMBER	The relation number you are trying to select does not exist in the administration.
INVALID_ARTICLE	The article you are trying to select does not exist in the administration.
INVALID_DISCOUNT_PERCENTAGE	The discount percentage you are trying to apply is not valid.
INVALID_RECEIPT_FOOTER_CODE	The code you are trying to add to the receipt footer is not valid. E.g. there are incompatible characters for the selected code type.
INVALID_RECEIPT_FOOTER_CODE_TYPE	The type of the code you are trying to add to the receipt footer is not valid. The currently supported types are code128 (default) and qrcode.
LINE_CHANGE_NOT_ALLOWED	The change you are trying to perform through lineChanges is not allowed in the current event or session.
LINE_ADDITION_NOT_ALLOWED	The addition you are trying to perform through lineAdditions is not allowed in the current event or session.
LINE_DELETION_NOT_ALLOWED	The deletion you are trying to perform through lineDeletions is not allowed in the current event or session.
INVALID_EXTERNAL_PAYMENT_ID	The externalPaymentId you are returning does not match what the POS sent to your endpoint.
EXTERNAL_PAYMENT_ID_ALREADY_USED	The externalPaymentId being used has already been used in a previous external payment.
MISSING_REQUIRED_BODY	The response is missing a body, but this webhook always requires a body.
MISSING_REQUIRED_FIELD	The response is missing a specific field, but this webhook always requires this field in the body.
FINAL_AMOUNT_ADJUSTMENT_NOT_ALLOWED	You are trying to adjust the final amount paid through the external payment, but this is not allowed based on the current settings.
LOWER_FINAL_AMOUNT_NOT_ALLOWED	You are trying to lower the final amount paid through the external payment, but this is not allowed based on the current settings.
HIGHER_FINAL_AMOUNT_NOT_ALLOWED	You are trying to raise the final amount paid through the external payment, but this is not allowed based on the current settings.
HTTP_PARSING_ERROR	A parsing error occurred when parsing the body.
WEBHOOK_CANCELLED_BY_USER	The webhook was manually cancelled from the user interface by the user.
RESPONSE_NOT_ALLOWED_HERE	The response you are giving is not allowed in the current event or session.
UNEXPECTED_FIELD	The response body contains an unexpected field.
WEBHOOK_TIMED_OUT	The webhook endpoint timed out.
ACTIVE_SESSION_CHANGED	The active session in the pos doesn’t match the sessionId in de request/response.