Field '&1'(&2-&3) cannot be maintained in general

What causes this issue?

You have tried to change a field that cannot be changed by a user.
There are several possible reasons for this:
It is a field defined by the system (for example, a client)
It is a field determined by the system (for example, shipment number,
overall status, settlement or calculation status)
The field contains administrative data determined by the system (for
example, date, time, user for creating/changing)

System Response

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.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.