SAP Message C5666 - You cannot change task list/recipe & because of change rule &

Diagnosis
You want to create, change, or delete data for task list/recipe &v1&.

System Response
The selected function is not carried out since you can only makechanges according to the change rule. You called the maintenancetransaction without regard to the change rule.

Procedure
Restart the maintenance transaction. On the initial screen, enter achange number that agrees with the change rule and allows changes.