--- title: Manage errors url: amazon-pay-api-v2/error-handling.html --- Amazon Pay returns a `reasonCode` and `message` if there is an error with your API request. As an example, below is the response if a request is submitted with an invalid parameter value: ```JSON { "reasonCode": "InvalidParameterValue", "message": "The value provided for [Parameter] is invalid." } ``` * TOC {:toc} *** ### Error codes This table describes generic error codes that Amazon Pay API endpoints can return.

HTTP status code	Reason code	Description
400 BAD_REQUEST	InvalidHeaderValue	You submitted an invalid value for at least one of the header parameters of your API call For details, check the message element in the API response
400 BAD_REQUEST	InvalidRequest	You request is invalid For details, check the message element in the API response
400 BAD_REQUEST	InvalidParameterValue	You submitted an invalid value for at least one of the parameters of your API call For details, check the message element in the API response
400 BAD_REQUEST	InvalidRequestFormat	You submitted a request in invalid JSON format. Validate request body format
400 BAD_REQUEST	MissingHeader	One of the header parameters is missing in the API call For details, check the message element in the API response
400 BAD_REQUEST	MissingHeaderValue	One of the header parameters is missing in the API call For details, check the message element in the API response
400 BAD_REQUEST	MissingParameterValue	One of the mandatory request parameters is missing in the API call For details, check the message element in the API response
400 BAD_REQUEST	UnrecognizedField	You have passed an invalid field in the request body For details, check the message element in the API response
400 BAD_REQUEST	InvalidSandboxSimulationSpecified	You have attempted an invalid operation for the Sandbox environment For details, check the message element in the API response
400 BAD_REQUEST	DuplicateIdempotencyKey	The IdempotencyKey that you have specified in this request was already used in a different request, and cannot be reused
400 BAD_REQUEST	InvalidParameterCombination	You attempted to use an invalid combination of parameters, check your request
400 BAD_REQUEST	CurrencyMismatch	Currency code provided in Charge does not match the currency set during checkout
400 BAD_REQUEST	InvalidAPIVersion	You have either attempted to use an unsupported API version or the API object version and API request version are incompatible
401 UNAUTHORIZED	UnauthorizedAccess	The specified merchant account is not authorized to execute this request For example, you attempted to make a request using delegated authorization that you aren't authorized to execute
403 FORBIDDEN	InvalidAuthentication	Authentication was not successful, check the status of your credentials in Seller Central (US, EU, JP)
403 FORBIDDEN	InvalidAccountStatus	Your account or merchant's account is not in an appropriate state to execute this request For example, your account has been suspended or you have not completed registration. Visit Seller Central (US, EU, JP) for more information
403 FORBIDDEN	InvalidRequestSignature	The signature in the Authorization header of your API call is invalid For details, check the message element in the API response
403 FORBIDDEN	InvalidAuthorizationToken	The authorization token passed in the request is not valid
404 NOT_FOUND	ResourceNotFound	Couldn’t find requested resource
405 METHOD_NOT_ALLOWED	UnsupportedOperation	Operation not supported
405 METHOD_NOT_ALLOWED	RequestNotSupported	HTTP method not supported For details, check the message element in the API response
408 REQUEST_TIMEOUT	RequestTimeout	The request timed out Retry the request. However, retry does not guarantee a successful response
426 UPGRADE_REQUIRED	TLSVersionNotSupported	TLS version not supported. Upgrade to the latest SSL/TLS version
429 TOO_MANY_REQUESTS	TooManyRequests	The request is throttled, due to too many requests in a given amount of time You should retry the request
500 INTERNAL_SERVER_ERROR	InternalServerError	There was an unknown error in the service Retry the request. However, retry does not guarantee a successful response
503 SERVICE_UNAVAILABLE	ServiceUnavailable	The service is currently unable to handle the request, due to a temporary overloading or maintenance Retry the request

*** ### Retrying errors You should immediately retry a request if you receive a response with a 408, 429, 500, or 503 HTTP status code. If you want to retry multiple times, we recommend that you implement an **exponential backoff** approach up to a defined limit, and then log the error and proceed with a manual follow-up and investigation. For example, you can time your retries in the following time spacing: 1s, 2s, 4s, 10s, and 30s. The actual backoff times and limit will depend on your business processes.