Issues with PayPal Integration, please help

Hey there - I am having a PayPal integration issue. When I try to test out a transaction, I receive this error: There was a problem connecting with the paypal gateway. (CODE)550001 User is not allowed to perform this action

I'm not sure why I'm receiving this error, as I have followed all the PayPal instructions including submitting an Application to PayPal to receive an Application ID. Our application has been "conditionally approved" and I have input our "Live App ID" into the plugin.

Please let me know if you have a fix for this error. We have everything else set to go and we were hoping to launch tomorrow.

Thanks in advance,

Jeff