Error fix
How to fix “502 Bad Gateway”
A proxy or edge server received an invalid or empty response from an upstream server.
Updated Apr 20, 2026
Tools that help with this
Fastest fix
Start here first. Step 1 fixes most cases—then work down the list.
- Bypass CDN temporarily to hit origin directly and compare status codes.
- Increase or align timeouts between proxy and app if logs show slow queries.
- Verify upstream health checks and pool membership in your load balancer.
Why this works
These steps work because it removes the most common source of mid-request resets: VPN/proxy interference, and it helps isolate CDN edge issues vs your origin server.
What this means
Something between the client and your app (CDN, load balancer, nginx) could not complete a valid response from the next hop.
Common causes
Origin down or restarting
Container cold start, crash loop, or TCP connection refused to the app port.
Protocol/timeouts
TLS mismatch, keepalive issues, or upstream slower than proxy timeout.
Step-by-step fix
Isolate upstream
- Bypass CDN temporarily to hit origin directly and compare status codes.
- Increase or align timeouts between proxy and app if logs show slow queries.
- Verify upstream health checks and pool membership in your load balancer.
Related
Also see: 502 — browse the HTTP status hub.
FAQ
- 502 only for some users?
- Often a single bad origin in a pool or regional edge issue—check per-POP or per-AZ metrics.
- 502 after deploy?
- Roll back, verify listen address/port, and health check paths on the new version.
- 502 vs 504?
- 502 is often bad/empty response; 504 is usually a timeout waiting for upstream.
Fix related issues
Still stuck? Try these related fixes next.
- Kubernetes CrashLoopBackOffThe container exits repeatedly—check logs, probes, and resource limits.
- Heroku H10 — app crashedThe web process exited; Heroku serves an error page. Logs show the real exception.
- Netlify — page not foundThe deploy exists but no asset matches the path—often SPA routing or a missing file in publish dir.
- Vercel — deployment not foundThe deployment URL or project alias does not exist or was removed.
- Cloudflare 525 — SSL handshake failedCloudflare could not complete TLS with your origin—cert mismatch, wrong port, or TLS version.
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Original error message
502 Bad Gateway