Hello Authorize.Net Support,
PayPal Express Checkout (authCaptureTransaction) consistently fails in the Sandbox environment, including on a brand-new Sandbox account with PayPal freshly enabled under Digital Payment Solutions. Production PayPal works for us.
Endpoint: https://apitest.authorize.net/xml/v1/request.api
Minimal request (no optional PayPal fields, no taxExempt, HTTPS URLs):
{"createTransactionRequest":{"merchantAuthentication":{"name":"<redacted>","transactionKey":"<redacted>"},"refId":"postman-test-001","transactionRequest":{"transactionType":"authCaptureTransaction","amount":"250.00","payment":{"payPal":{"successUrl":"https://www.example.com/success","cancelUrl":"https://www.example.com/cancel"}}}}}
Response: messages.code E00027 ("The transaction was unsuccessful."), transactionResponse.responseCode 3, rawResponseCode 0, accountType PayPal, errors[0].errorCode 57 ("An error occurred during processing. Please try again."). No secureAcceptance URL is returned. The Merchant Interface shows the transaction as "General Error" with Digital Wallet = PayPal.
Affected transaction IDs:
- 120091020445 (new Sandbox account, minimal request via Postman)
- 120091018531, 120091015105, 120091015097, 120091012909 (earlier Sandbox account, via .NET SDK)
- 80060242123 (Postman; this one returned sub-error 19 instead of 57)
What we tried: minimal request with only successUrl and cancelUrl; unlinking and relinking PayPal with a new PayPal sandbox business account; creating a new Sandbox account. The result is identical each time, so we believe this is a Sandbox-to-PayPal connectivity or configuration issue on the platform side. A similar report exists in the developer community: "PayPal Integration - Sandbox Communication Errors" (June 2026).
Could you please check the PayPal Sandbox connection on your side and tell us whether there is a known issue or a required configuration step we are missing?
Thank you,
Lokendra
4haM26X695
