It's possible that your payment has been stopped by Paypal's internal security system.
To provide a safe online payment service Paypal's internal security system reviews every payment before it's approved. Occasionally, Paypal must stop a payment. This is similar to the way most banks and credit card companies work. When a payment is stopped, it's not a reflection of you or your account activities, but rather they have noticed a pattern associated with higher-than-normal risk.
Here are some things you can do to help improve the chances of successful payments on Paypal: