Problem was solved when I turned off monthly billing in Websites Payment Pro. HELP! PayPal Pro is the only plugin I'm using. I've established a Payments Pro account on PayPal with the required API signature and carefully followed all the installation instructions. Tech support at aMember is doing what I'd call "log rolling" i.e. repeating the same general instructions. I've exchanged several emails with PayPal tech support and even talked to a technician who assured me that I'm ok on their end. My setup is simple: I use GoDaddy.com for hosting (linux/unix) and I have only two products: a 60-day free trial and then $20/year with no recurring billing. Registration and protection are working just fine. It's only payments that are a problem. Any thoughts?