Membership PayPal Redirect

Hi,

We are setting up the membership plugin and everything seems fine until we get to the payment page with the PayPal button. It just stays on the same page and does not redirect to PayPal. We are using PayPal Express given the renewal aspect. Any thoughts on what could be causing this?

Related note, what are the odds of integrating Stripe.com payment gateway here, like you have on MarketPress.