Why isn't Authorize.Net working?

Error message: Authorize.Net FDC Merchant ID or Terminal ID is incorrect

There is an issue with your Authorize.Net Merchant Service Provider or with your Authorize.Net account itself. Please report this error to the Authorize.net customer support.

Error message: (123) This account has not been given the permission(s) required for this request

Check that you're using the correct API Login ID for your Authorize.Net account credentials in the Payment settings of your Online Store:

Error message: (99) This transaction cannot be accepted

Check that the Transaction Key you entered in your online store matches the current Transaction Key in your Authorize.Net merchant account.

Error message: (13) The merchant login ID or password is invalid or the account is inactive

Check that the details you entered in your online store match your live Authorize.Net merchant account.

Error message: (14) The referrer, relay response, or receipt link URL is invalid

Edit the Relay Response/Receipt URL in your Authorize.Net merchant account:

1. Log in to your Authorize.net merchant account.
2. Go to the Receipt/Response URLs page.
3. Click Add URL.
4. Enter https://app.shopsettings.com/authorizenet/STORE_ID (where STORE_ID is the ID of your store account that you can see in the store admin, in the bottom left corner) to the URL field.
5. Click Submit.