Thanks for your interest in QCAD.
I cannot assist much with PayPal problems, unfortunately. There might be a problem with account restrictions, funding, account preferences, etc.
There are no known problems on our side at this time.
Alternatively, you can always send us the full amount through PayPal using the 'Send money' interface in your PayPal account.
Our PayPal e-mail is: firstname.lastname@example.org
After successful payment, I will push your order through manually.
If you cannot make it work with PayPal, please check out using one of the alternative payment options.