I am trying to perform a DEM analysis using Abaqus.
When I create a model and let it calculate, the following error is displayed in the sta file.

***ERROR: In current parallel DEM implementation, it is not supported that
only a subset of the DEM nodes are included in general contact.
Either rerun the test in serial or modify the model to include all
DEM nodes in general contact.

Under what conditions does this error occur?
Can you tell me how to avoid this error?