Is this for your game Gulch Defense ? I just downloaded without issues. Can you confirm how you found out users can’t download/buy your project?
I don’t know about payments, but your project can definitely be downloaded.
Have you linked a paypal/stripe account to accept payments with? If you provide more details over what error your friends see, it would be easier to find this issue.
If in doubt, you can always contact support, as they have bigger visibility over your account and what needs fixing (if anything).