LinkedIn publishes no flag for a shadow ban. What it publishes is that policy enforcement may limit the visibility of an account and that ranking can taper distribution, neither with a notice. People notice the state in a fixed order: invitations stop getting accepted, then replies dry up, then post reach sags. This tool tests the one half of the first symptom that can be observed from outside your account in minutes: whether an invitation you send reaches its recipient at all.
It cannot see whether your posts are being shown less, and it cannot tell a dropped invitation from one you never sent. So read the result as one line of evidence. Arrived rules out the loudest fear: your account can still send and be received. Not arrived is worth taking seriously only after the mundane causes are excluded, and the page tells you which ones. For the full diagnosis, the search test, the impressions baseline and the recovery sequence, read the LinkedIn shadow ban guide.