Paypal Invalid Merchant Configuration sandbox error

Question

I am using paypal pro in sandbox. when I send the request and in response I get this error:

Array ( [TIMESTAMP] => 2010%2d11%2d23T09%3a21%3a12Z [CORRELATIONI

Answer 1

Click products and enable payment pro sorted it for me.

Update Aug 12, 2013: Enabling PayPal Payments Pro has been moved to the "Profile" tab. There is no longer a "Products" tab.