Thanks for your inquiry. ~ We appreciate your patience :-)
Could this be caused by setting PayPal sandbox to yes? I don’t remember turning sandbox on at all. Has there been any case of s2Member Pro installation resetting PayPal options?
No, not that I’m aware of. I haven’t seen that reported by anyone.
If you are using HTML code for your PayPal Buttons, you will need to regenerate your PayPal Buttons after turning Sandbox Mode off, so that URLs in your Button Code do not reference sandbox.paypal.com. It appears you’ve already done this.
If you’re running s2Member Shortcodes for your PayPal Button (recommended), then you will not need to worry about this, because turning Sandbox Mode off will automatically modify the HTML generated by s2Member’s Shortcodes.
If problems persist, please use s2Member’s Shortcodes. Please post a copy of your Shortcode for us to review with you. If we can’t resolve the issue after a review of your Shortcode, we’ll run diagnostics for you.