No kanban containers exist

What causes this issue?

You want to post the goods receipt for a receipt element (for example,
purchase order, production order, run schedule quantity) that will
result in the replenishment of a kanban container. However, no empty
containers were found that suits this receipt element.

System Response

The following reasons may exist:
a GR has already been posted for the receipt element and the status of
the corresponding container has been changed to FULL.
The GR is posted late and in the meantime, a new receipt element has
been created for the corresponding container.
If a scheduling agreement is used, the GR quantity of a previous GR is
distributed among the containers in such a way that at least one
container is refilled with less than the target quantity and is still
set to "FULL".
If you are dealing with a goods receipt for a purchase order, a
production order or a reservation, this message is issued as a warning.
If it is a goods receipt for a scheduling agreement, the system issues
the message as an error as in this case, no schedule lines can be
calculated for which a goods receipt quantity is still open.

How to fix this error?

If the system displays a warning, you have the following options:
You post the GR without reference to the container. To define where the
material is to be delivered proceed as follows:
In the kanban board (demand source view), you can determine the control
cycle(s) in which the material is used via the material number and the
receiving storage location. Here, enter the plant and the receiving
storage location in the initial screen of the plant and in the resulting
list, search for the control cycles for the material number.
You can also terminate the processing (for example, if you first want to
correct the data to post the goods receipt with reference to a kanban
container.)
If the system displays an error message (scheduling agreement
processing), you cannot post a goods receipt until an empty kanban
container with an open schedule line is available.

Error message extract from SAP system. Copyright SAP SE.