The default value calculated by the system for & will be reset

What causes this issue?

The default value calculated by the system was reset.

System Response

The system has locked the field again to prevent data from being
entered.

How to fix this error?

You can cancel the lock again, and then enter a different date.

Procedure for System Administrators

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.