state_storage_unavailable

What happened

The page has no storage of that kind, or refused the write, so the stored signal keeps its value in memory alone.

What to do

On the server, read the signal's initial value and let the browser take over; in a browser that refuses storage, such as a private window with it off, the signal still works for the page.

The arguments of the specific occurrence are in the query string of the URL the error gave you.