Check your settings
One of the most common reason that an order has yet to send is the message isn't due to send it yet based on your campaign settings. You should always check your campaign settings and try to work out when the order's message would be scheduled to go. Please find an example timeline below,
May 1st: Order Received
May 3rd: Order Dispatched
May 10th: Order delivered
May 20th: Message sent (As campaign set to sent 10 days after delivery)
As you can see, it can be a while after you get the order that the message is sent, depending on your settings. You can see when feedBAKER plan to send your messages by going to 'Campaigns', and the 'Pending' tab. Here you can see messages due to go in the future and can also filter these by Campaign or order if you're unsure.