Lab Requester could not start.

The page loaded but the application code never ran, so nothing has been lost — there was no session to lose. This is a delivery problem, not a crash in the app.

Try a hard reload first (Ctrl+Shift+R). If it persists, open the browser console — the first red line names the file that failed to load and is the only thing that distinguishes the causes.

If that line says a .js or .css file came back as text/html, the app was never asked for — something in front of it answered instead, usually a security challenge. Redeploying does not help: the same source builds the same filenames. Check the console for a blocked inline script just above, and see public/_headers.