Notice: Undefined variable: WA_Authorize_Net_API_Credentials_x_test_request
I recently updated my site from mysql to mysqli. Now I'm getting the following error when I place an order. The order does get sent to and approved by authorize.net, but I don't get an email receipt from my site and I get this error rather than the checkout success page.
Notice: Undefined variable: WA_Authorize_Net_API_Credentials_x_test_request in /home4/user/mysite/confirm.php on line 73