Side note: I tried the Event Espresso “test” credit card number and I also tried my PayPal Sandbox Developer “test” credit card number, both with same result. I’ve seen the source code on my registration page and there are some references to “http” in there… could that be what’s causing the security issue? Is there a workaround here? Can I embed the form on a secure page? Not sure if that would help, since the seemingly non-secure code is IN the form, but it would be worth a shot at this point? Thanks again!