Just happend to me too. Reject and no way to fix an issue.
SKPaymentQueue: 0x6000026942e0>: Payment completed with error: Error Domain=ASDErrorDomain Code=500 "Unhandled exception" UserInfo={NSUnderlyingError=0x600002a09f50 {Error Domain=AMSErrorDomain Code=301 "Invalid Status Code" UserInfo={NSLocalizedDescription=Invalid Status Code, NSLocalizedFailureReason=The response has an invalid status code}}, NSLocalizedFailureReason=An unknown error occurred, NSLocalizedDescription=Unhandled exception}