Why is the payment I received under review?
PayPal reviews all transactions to help sellers avoid risk. If we think that a payment might be risky or fraudulent, we'll review it and ask you to wait until our review is complete before posting the sold item. This review can take up to 24 hours.
We'll let you know by email and/or on the Transaction Details page when it's ok to send an item for which a payment has been under review. Payments that complete the Payment Review may be eligible for Seller Protection as long as the transaction follows Seller Protection guidelines.