Select layout with blocking reasons

What causes this issue?

You tried to delete a blocking reason. You must position the cursor
on a reason. The display variant you are using does not display any
blocking reasons. Therefore, it is not possible to delete a blocking
reason.

How to fix this error?

Select a display variant which displays blocking reasons via the menu
<LS>Settings</> --> <LS>Line layout</>.

Error message extract from SAP system. Copyright SAP SE.