System table & not allowed in piece list

What causes this issue?

The protected system table &V1& could not be included in the object
list of object &V2& of type &V3&, because system table entries
are not maintained and transported as simple table entries.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

The entry is rejected.

Error message extract from SAP system. Copyright SAP SE.