Authorize.net PHP API E00013 The field is invalid

KT1984 — Sat, 30 May 2026 03:02:19 GMT

Yesterday transactions started failing while using authorize.net php API. But after looking at the logs, the transactions weren't failing at all. In fact, I get response code 1: {"code":"1","description":"This transaction has been approved."}. However, I also get: {"code":"E00013","text":"The field is invalid."} at the same time, which was triggering my fail logic. I changed my fail logic so the transaction goes through on my site but would like to know what is causing the error E00013. It gives no reference. I did a basic test that uses only a card and amount, and the error still comes through in the response. I literally checked each field and then did nothing but test card data and amount. I have no idea what to do now?? Any help would be appreciated.

topic Authorize.net PHP API E00013 The field is invalid in Integration and Testing

Authorize.net PHP API E00013 The field is invalid