502 on every target
Likely causes
- - Endpoint temporarily unhealthy
- - Wrong port maps to a dead service
Verified remedy
Re-copy endpoint values, test with curl -x, and swap to a spare endpoint if the failure persists.
Proxy troubleshooting
Fix 502 bad gateway from proxy
Ranked causes, ordered diagnostics, and a verified remedy for 502 bad gateway from proxy - ending with a final connection check.
Quick answer
Fix: 502 Bad Gateway from the proxy. Confirm endpoint values, test with curl through the endpoint, apply the matched remedy, then re-verify the exit IP is your assigned endpoint.
Exact symptom text
Causes ranked by likelihood
Ordered diagnostics
Final connection check
When this is the right fit
- Exact symptom text
- Causes ranked by likelihood
- Ordered diagnostics
Who this page is for
Ranked causes, ordered diagnostics, and a verified remedy for 502 bad gateway from proxy - ending with a final connection check.
Fix: 502 Bad Gateway from the proxy. Confirm endpoint values, test with curl through the endpoint, apply the matched remedy, then re-verify the exit IP is your assigned endpoint.
Diagnosis tree
502 on heavy pages only
Likely causes
- - Upstream timeouts on slow targets
- - Connection pool exhaustion
Verified remedy
Reduce concurrency and increase client timeout; dedicated endpoints fail predictably under load you control.
Final connection check
- 1Apply the remedy for the matched symptom
- 2Test the endpoint directly with curl -x or --socks5-hostname
- 3Repeat the original action in the tool
- 4Confirm the exit IP is the assigned endpoint
Working connection
The original action completes and the exit IP matches the endpoint.
Broken connection
If curl through the endpoint also fails, the problem is endpoint-level: check dashboard status or swap to a spare endpoint.
Sources
Facts last reviewed 2026-09-01.
Prevent it recurring
A 502 from the proxy means the proxy could not reach or finish the upstream request; separate proxy health from target health with a direct curl test.
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Frequently asked questions
How do I fix 502 bad gateway from proxy?
Work the diagnosis tree top to bottom: confirm endpoint values, test with curl through the endpoint, apply the remedy, then run the final connection check.
Why does this keep coming back?
Recurring proxy failures usually trace to an unstable mapping - rotating endpoints or shared addresses. A dedicated static endpoint per profile makes behavior predictable.
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