Task &1 cannot be executed with status "blocked"

What causes this issue?

You can only execute a task in update mode when it does not have a
"blocked" status or an "irrelevant" status.
Task &V1& is currently blocked and cannot be executed.

System Response

Error message

How to fix this error?

In order to execute task &V1& in update mode, unblock it first.

Error message extract from SAP system. Copyright SAP SE.