Work item &: Task & locked for instantiation

What causes this issue?

The work item cannot be created as the relevant task is locked for
instantiation (that is for creation of new work items).

System Response

Creation of the work item was terminated.

How to fix this error?

Unlock the relevant task.

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

INCLUDE NA_WF-ADMINISTRATOR OBJECT DOKU ID TX

Error message extract from SAP system. Copyright SAP SE.