When selling on Amazon, your orders may not all process at the same rate; there are times when orders have "Pending" status. Amazon gives buyers a grace period to change their minds about purchases, so all orders are Pending for 30 minutes after they're placed. If an order shows Pending status after 30 minutes, there may be a problem with the buyer's payment, a hold on shipping, or an issue with unusual activity on your account.
Payment Verification Problems
Amazon gives orders Pending status until payment is verified. There may be a delay if buyers have out-of-date credit card details or if their payments are refused. This can extend the order process to up to 21 days. You should not ship Pending orders. If buyers contact you, refer them to Amazon Payments.
Multiple Item Orders
If you use the Fulfilment by Amazon (FBA) service, you store your products at an Amazon center so Amazon ships for you. If a buyer orders multiple items through FBA and has free shipping, your part of the order may show as Pending until Amazon collects all the items. Even if Amazon splits shipping and delivers your item before others, it retains Pending status until Amazon fulfils all the order.
Amazon sets monthly velocity limits on seller accounts. If you sell a lot more than usual in any month, Amazon may evaluate your account for fraudulent activity. Any orders you get during a velocity limit review show as Pending. If there is no problem, your orders will move from Pending to Shipping status. If Amazon spots a problem, it reviews your account. You should get a notification in the Customer Metrics area of your account if this happens.