Im not sure if this is a problem with my 2checkout accoutn but when I try to pay a test invoice through 2checkout(in demo mode), 2 checkout takes me to an error page stating that incorrect parameters were provided.
I looked in viewinvoice.php source code and realized that all the parameters being sent to https://www.2checkout.com/2co/buyer/purchase are prepended with "x_" as in "x_Address" or "x_First_Name" while 2checkout info page says that "Address" or "First_Name" need to be sent.
Is is an error on WHMCS side or is my 2CO account not configured properly?