lm_paypal subscription

i have added a subscription for 1 month and assign it to specific role. set permissions "access lm_paypal_subscribe " for authenticated user, admin, members(role). i have copy and paste subscription button code and paste in a block with input filter "php code". but i am unable to see any subscription button.
second thing i have provided LM PayPal Business/Premier Email which is sellers paypal sandbox email. when i visit my account and click "proceed to paypal" it redirect me to https://www.sandbox.paypal.com/cgi-bin/webscr. what wrong i m doing? plz help me.
thanx.