No payment data was returned

Hi all,

I have been trying to setup Paypal (latest version) but I end up getting a "Could not verify the Paypal transaction as no payment data was returned" message. It seems like Paypal isn't sending a transaction id back.

I have activate payment data transfer in PayPal settings.

Looking at the weblogs it seems nothing is posted or send to above URL.

Does anyone have any suggestions? Thanks!
Don't have a clue why it didn't work in Sandbox mode, but it works fine in production mode...

By the way: Make sure your PayPal account is a business account and fully verified! Without having a fully verified account European business owners won't be able to receive over 2500 Euro per year.
The Paypal sandbox is extreeemely buggy. It's unfortunalty rule rather than exception that something is broken there.
Sorry to dig this old thread, but I believe its (likely) answer deserves to be documented.

One has to provide the module with the sandbox PDT, which is different than the production one.  That is, the procedure described in the wiki has to be also performed on the sandbox seller account on sandbox.paypal.com.