You may encounter this error in a number of places. most commonly when you attempt a refund of an Authorize.net transaction.
For some reason, some Auth.net users need to manually activate the Transaction API. To do this follow these steps:
- Log on to the Merchant Interface at https://account.authorize.net
- Select Settings under Account in the main menu on the left.
- Click the Transaction Details API link in the Security Settings section. The Transaction Details API screen opens.
- If you have not already enabled the Transaction Details API, enter the answer to your Secret Question, then click Enable Transaction Details API.
- When you have successfully enabled the Transaction Details API, the Settings page displays.