Your customer has revoked your nomination and chosen another haulier for the container(s). You can tell that this is the case because the container is visible in the Handlings dashboard but is no longer visible in Shipments.
If a transport order exists in your own TMS but there is no registration in the PCS, it is no longer valid.
The customer should always inform the haulier of the cancellation or removal of a container in order to avoid a cargo mismatch, because the haulier may have already initiated transport to collect the container.