Hi Deian,
Unfortunately I have the same issue - "Your order is not confirmed yet, this page will refresh in 5 seconds! Please do not navigate away from the page until we receive your order confirmation." I receive this message with LIVE and sandbox testing.
1. Instant payment notifications within PayPal is enabled
2. I am using my main paypal account
3. Default currency "Euro" is configured, but currency in button code is empty
4. The payments status is set as completed/verified
5. Received PayPal payment confirmation via email
6. Did not receive Email from my website including the download link (although Email Delivery is configured with "on")
7. And of course was not redirected to Thank you page (although Thank you page is configured with "on")
Can you please help me again?
Thanks and best regards,
Doreen