Dynpro &1 in program &2 either does not exist or is not used

What causes this issue?

The screen does not exist or is not used in the program.
It may be called dynamically.

System Response

You cannot display the call hierarchy for this object.

How to fix this error?

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

Error message extract from SAP system. Copyright SAP SE.