Hi, I am a newbie at authorize.net, I need a tutorial step by step to connect my web with authorize.net, anyone kindly help me?? 

I've tried, but only produces this :

via direct_post.php

An error occurred while trying to report this transaction to the merchant. An e-mail has been sent to the merchant informing them of the error. The following is the result of the attempt to charge your credit card.

      This transaction has been approved.

It is advisable for you to contact the merchant to verify that you will receive the product or service.

via sample_codes

Error!

We're sorry, but we can't process your order at this time due to the following error:

  The merchant login ID or password is invalid or the account is inactive.

response code 3

response reason code 13 

 Help me please :mansad: