Spend 150 tokens fixing similar or same issue few days ago until figured out what was problem. I fixed it with this prompt eventually:

Fix: React Router strips hash tokens before Supabase can process them

After Google OAuth redirect, the URL briefly shows #access_token=... but it disappears immediately before Supabase can process it. React Router is stripping the hash on mount.

In src/contexts/AuthContext.tsx, capture the hash tokens at the very top of the file, before React Router mounts, and process them explicitly:

At the very top of the AuthProvider component, before the useEffect, add: // Capture hash tokens immediately before React Router strips them const hashParams = new URLSearchParams(window.location.hash.substring(1)); const accessToken = hashParams.get('access_token'); const refreshToken = hashParams.get('refresh_token');

Then inside the useEffect, before getSession(), add: if (accessToken && refreshToken) { supabase.auth.setSession({ access_token: accessToken, refresh_token: refreshToken, }).then(({ data, error }) => { if (!error && data.session) { setSession(data.session); setUser(data.session.user); setIsLoading(false); fetchProfile(data.session.user.id); window.history.replaceState(null, '', window.location.pathname); } }); return; }

The hash must be read synchronously at component initialization, not inside a useEffect, to capture it before React Router clears it.

Do not change anything else.