Data for specified key areas unchangeable

What causes this issue?

Certain key areas of the table/view are locked for manual changes in
this system, by the Customizing Distribution.

System Response

You cannot change these data records or create new data records in the
locked key areas.

How to fix this error?

You can only make changes in system &V1&.

Procedure for System Administrators

If the necessity for the change is specified, contact the system
administrator.

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

The system administrator checks which of the options named below is the
cause of the lock. To do this, you must log on to the SAP Solution
Manager system.
The system determined above is the source system of an active
Customizing distribution with editor lock in the target system
(transaction SCDT_SETUP). You can now make Customizing changes for the
selected table / view only in source system &V1&.
The system &V1& determined above is the central system (that is, the SAP
Solution Manager system) of a local lock. The selected table / view was
explicitly protected against Customizing changes in this client. You can
only make Customizing changes by removing the lock (transaction
SCDT_LOCK) or by the user-specific local assignment of the authorization
for S_TABU_DIS with activity BD.
Decide with your system administrator which solution is the right one
for you.

Error message extract from SAP system. Copyright SAP SE.