In most cases, your carriers manifest will contain your shipment tracking numbers on the print out. In some cases, it may not. Here's an easy way to double check a tracking number against your recent manifests.
Go to your manifests page
Click on the orange, "Create new manifest" button
Click on the Fetch previously generated EasyPost manifests hyperlink text at the bottom left:
In the window that appears, search for that tracking number in the list.
If you see it on the list, your tracking number has been included for manifesting. If you need any assistance, reach out to support in chat with your tracking number for more help!