Why is my session getting dropped after login in my app?

A session usually gets “dropped after login” when the app thinks the user is authenticated, but the browser/client does not keep sending the same session cookie/token on the next request. Common causes:

1) Cookie settings are wrong

If you use session cookies, check:

• HttpOnly: should usually be on
• Secure: must be on if you’re using HTTPS
• SameSite: Lax is often fine; None requires Secure
• Domain / Path: if these are too restrictive, the cookie won’t be sent back
• Expiration / Max-Age: cookie may be expiring immediately

2) HTTPS / proxy misconfiguration

If your app is behind a reverse proxy or load balancer:

• The app may think the request is HTTP, so it won’t set/send secure cookies correctly
• Ensure proxy headers are configured correctly (X-Forwarded-Proto, etc.)
• Make sure the cookie Secure flag matches the real external traffic scheme

3) CORS / credentials issues

If login happens via API calls from a different origin:

• The client must send credentials (fetch(..., { credentials: "include" }) or equivalent)
• Server must allow credentials in CORS
• Access-Control-Allow-Origin cannot be * when using credentials

4) Session store problems

If using server-side sessions:

• The session store (Redis, database, memory) may be clearing/restarting
• In-memory sessions will be lost when the process restarts or scales to another instance
• Multiple app instances need a shared session store or sticky sessions

5) Load balancer / sticky session issues

If one request goes to server A and the next to server B:

• Session may not exist on the second server unless stored centrally
• Use a shared session store or configure sticky sessions

6) Login flow not persisting session

Some frameworks require explicitly saving the session after setting auth data:

• Session changes may not be written before redirecting
• Middleware order can matter

7) Token storage issue

If you use JWT or auth tokens instead of sessions:

• Token may not be stored correctly
• It may be stored in memory and lost on refresh
• Authorization header/cookie may not be attached on later requests

8) Browser issues

• Third-party cookie blocking
• Incognito/private mode restrictions
• Cross-site login flows without proper SameSite=None; Secure

Quick checks

1. Open browser devtools → Application/Storage → inspect cookies after login
2. Confirm the cookie is actually set
3. Check whether the cookie is sent on the next request
4. Compare login response headers and subsequent request headers
5. Look at server logs for session ID changes or missing session IDs

If you want, I can help you debug it step by step if you tell me:

• your backend framework
• whether you use cookies, server sessions, or JWT
• whether frontend and backend are on different domains
• what your cookie/session config looks like