There are several reasons why the payment may not be going through such as seller preferences, PayPal blocking the funding source for security reasons or an inability to gain a successful authorization from your card provider. I would encourage you to contact your card issuer just to ensure they are not experiencing any issues with the card but also consider trying the following.
You mentioned the card was a debit card and with some debit cards they can be charged through our system as either a debit card or a credit card. Try making the payment again and follow these instructions after you have clicked on the 'Pay Now' button to see if the card can be charged as a credit rather than a debit.
1.On the "Check Payment Details" page, click the "Funding Sources" link at the top of the page.
2.Select the "Process via Visa Network" or the "Process via MasterCard Network" button.
3.Click "Submit."
If the payment goes through then all is fine but if you continue to experience issues then I would advise contacting PayPal directly so that we can look into this issue further. Thanks so much for being part of the community and have a great day.