How to Fix
Next.js Auth Issues

Why Auth Breaks in Next.js

Next.js has a split personality when it comes to authentication. You have server components, client components, API routes, and middleware — all interacting with auth in different ways. A change in one layer can break auth in another.

Add to that the complexity of session management, JWT configuration, OAuth providers, and cookie settings, and you have a system where small mistakes cause big problems.

Issue: Login Redirects Loop

The most frustrating auth bug: you try to log in, you are redirected to the login page, you log in, and you are redirected back to the login page. Forever.

Common causes: The callback URL does not match the configured URL in your OAuth provider or NextAuth. Session is not being saved correctly. Middleware is redirecting authenticated users back to login.

Fix: Check your NEXTAUTH_URL environment variable matches your production URL exactly. For OAuth, verify the redirect URIs in your OAuth provider console match your app URL (including http vs https and www vs non-www).

Issue: Sessions Expire Immediately

You log in, and within seconds or minutes, you are logged out again.

Common causes: JWT secret mismatch between production and development. NEXTAUTH_SECRET is different in each environment. Cookie settings have too short a maxAge.

Fix: Set NEXTAUTH_SECRET to a consistent value in production. Check your session cookie maxAge — it should be at least 30 days for a typical app. If using JWT strategy, make sure the secret is at least 32 characters.

Issue: Protected Routes Are Accessible

You expect certain pages to require login, but anyone can access them.

Common causes: Middleware is not deployed or not configured correctly. Client-side auth checks happen after the page renders. API routes do not check authentication.

Fix: Use Next.js middleware for route protection at the edge. Add auth checks to every API route. Use server components with session checks before rendering protected content.

Issue: OAuth Providers Not Working

Google, GitHub, or other OAuth logins fail with errors about invalid redirects.

Common causes: Redirect URI in OAuth console does not include /api/auth/callback/google. Localhost URLs in production. Missing scopes.

Fix: Add the exact production callback URL to your OAuth provider. For Google: add both your domain and localhost for development. Request the right scopes — email, profile, and any additional permissions you need.

Getting Help

If you have been debugging auth for more than a day, it is time to get expert help. Auth is complex and mistakes can introduce security vulnerabilities. We specialize in fixing Next.js auth issues — most are resolved in under 48 hours.