Planning type & is not allocated to an archiving category

What causes this issue?

The single records cannot be archived since no archive class is
allocated to the planning type.

System Response

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

How to fix this error?

Determine which archive class should be valid for the planning type.
<DS:TRAN.OT21>Proceed</>

Error message extract from SAP system. Copyright SAP SE.