Occasionally orders will show in Shiptheory as Not Available / Not Ready. This means that Amazon has let Shiptheory know that an order has been placed, but not all details for the order have been made available for Shiptheory to be able to book shipping for the order yet.
This normally happens when an order is still clearing Amazon payment authorisation checks. These usually only take a few minutes, occasionally up to half an hour and very occasionally a few hours. Please note that this is at Amazon's end and for any concerns over an order you should contact Amazon support.
As soon as the order has cleared the checks OK, Shiptheory will be notified, the order will be set to Ready and you will be able to book shipping. Any orders failing authorisation checks will not be updated and will remain in Not Ready status.