PayPal thinks Membership Transaction should be Encrypted

I have Membership installed. Rather complex to set up - UI.

After completing everything, I ran a sandbox test and it seemed to be working fine. I went live tonight.

No one was registering properly. One woman was kind enough to send feedback. It was looping and not proceeding when she tried registering with Facebook. I've since disallowed registration that way.

Then she registered with her email account, and when she subscribed and it directed her to PayPal she got a return-message that PayPal couldn't do any transaction with an unencrypted site. This is the first I'd heard of such a thing via PayPal.

I'm losing a few customers here for sure.

My payPal Account is set up for PayPal Payments Standard. And that or the single pay were the only two options in the payment gateway settings.

Appreciate your assistance solving this.

Cheers, Lee