The characteristics of object & do not exist in level &

What causes this issue?

Not all the characteristics of the source are in the target.

System Response

The status for this object is set to "Checked with errors". This object
cannot be reclassified until the error has been eliminated.

How to fix this error?

Check the characteristics of the two objects and attempt to maintain
these so that at least the characteristics and the characteristic values
of the source are defined in the target. Do not forget to take the
inherited characteristics into account too.

Error message extract from SAP system. Copyright SAP SE.