How To Fix UCS0031 - Blocking not possible: Task &1 has the status "&2" for &3

SAP Error Message - Details

• Message type: E = Error

• Message class: UCS0 - Messages for Status Management

• Message number: 031

• Message text: Blocking not possible: Task &1 has the status "&2" for &3

What causes this issue?

Task &V1& currently has the status &V2& for &V3&. Thus, the task &V1&
either cannot be blocked or no longer needs to be blocked, or blocking
is no longer supported.

System Response

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

How to fix this error?

Block tasks only when they in a blockable state. Tasks that do not
require manual interaction (that is, tasks other than data entry and
manual posting) are in a blockable state when their status is "Without
Errors," "Without Errors but with Warnings," "Unblocked," or "Pending
Completion of Preceding Task."
Manual tasks are the exception because these are blockable regardless of
the current task status.
Furthermore, all tasks that precede a given task must be blocked before
the given task itself can be blocked. This applies to all task
categories.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.