PayPal Express problem

[DrByte]

... uses Paypal Express Checkout, it takes them to Paypal, they click "Continue", then they see a page on my site that says, "Whoops! Your session has expired."

Which browsers is this happening with?

I originally left the Paypal IPN Website Payments Standard turned off, but after this problem I turned on Payments Standard with debug mode on.

Why did you use Standard in debug mode if you were having problems with Express? Why not enable debug mode in Express instead?

When I had a friend check out I got the same five debug error messages as the guy in this post had, including #2 "IPN FATAL ERROR :: No POST data available -- Most likely initiated by browser and not PayPal."

I'm not surprised. First, you'll get up to 12 emails per IPN if you have the IPN debug mode set to send emails. Second, if you're visiting the ipn_main_handler.php URL with your browser, then it's going to tell you that.

Do you think it's because of the shared SSL?

Unlikely. Didn't you say you had the problem *before* you gave an SSL URL?