Can't get Paypal 2 work for subscriber levels

I have the PayPal error page that says “transaction failed” once I setup membership buttons (level 1,2,3,4).
I’ve got all my parameters setup both on my site and on PayPal account, and what is very strange is that I’m able to use “specific post/page content” sells without a problem at all.

So my question is it optional to work with membership levels, or do I have to setup something with recurring billings on my PayPal account ?

Ok, I’ve noticed that my member level buttons are not working at all for any kind of transaction, unless I’m already connected to my PayPal account on the same browser (the account I’m using for the website transactions).

The Buttons for specific posts/pages is working fine so far.

All my parameters are activated both on paypal and S2 member such as “button encryption”
I’ve reviewed all account settings on both sides.

Can I have any support here ?
– I’ve just purchased pro version –