Only program & is currently permitted

What causes this issue?

The GUI of the program, the name of which you entered, should be active
in Table/View maintenance.
Technically only the GUI of the model function group of extended table
maintenance (SAPLSVIM, default value) or the GUI of the function group,
to which the maintenance modules of the Table/View are assigned, can be
currently used.

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?

Enter a permissible value.

Error message extract from SAP system. Copyright SAP SE.