Some carriers return a full transport plan when you ask by B/L. Others return almost nothing at
B/L level: no containers, no milestones, sometimes only the port of loading and port of discharge.
The same carrier will often answer properly when asked by container number instead.
This is a property of the carrier, not of your shipment. It is more common with
smaller and regional carriers.
What to do: add the container numbers to the tradeflow. Where the carrier supports
tracking by container, tracking starts from there. Note that a container-level answer is sometimes
limited to the latest milestone rather than the full journey.
Example
A regional carrier shows only a port of loading and port of discharge for a B/L, with no containers or milestones. When the container numbers are added to the tradeflow, tracking starts. The answer may show only the latest milestone, not the full journey.