Task list not free for use

What causes this issue?

The <GL:maintenance_task_list>task list</> that you have chosen has a
status that does not allow it to be used freely.

System Response

The system will not allow you to choose this task list.

How to fix this error?

Check whether you have chosen the correct task list.
If you have chosen the right task list, check why the task list cannot
be used freely. If necessary, assign the task list a status that will
allow you to use it.

Error message extract from SAP system. Copyright SAP SE.