Proxy troubleshooting
Ranked causes, ordered diagnostics, and a verified remedy for http2 protocol error through proxy - ending with a final connection check.
Quick answer
Fix: HTTP/2 protocol error via proxy. Confirm endpoint values, test with curl through the endpoint, apply the matched remedy, then re-verify the exit IP is your assigned endpoint.
Ranked causes, ordered diagnostics, and a verified remedy for http2 protocol error through proxy - ending with a final connection check.
Fix: HTTP/2 protocol error via proxy. Confirm endpoint values, test with curl through the endpoint, apply the matched remedy, then re-verify the exit IP is your assigned endpoint.
Likely causes
Verified remedy
Force the client to HTTP/1.1 for the test; if it passes, keep HTTP/1.1 through this path or use a proxy that tunnels HTTP/2 untouched.
Likely causes
Verified remedy
Keep one client per endpoint and align client timeouts with endpoint idle windows.
The action completes and the exit IP matches the endpoint.
If curl also fails, the endpoint is unhealthy: swap to a spare.
Facts last reviewed 2026-09-01.
Tunneled HTTP/2 should pass untouched; framing errors indicate something terminating the connection in the middle.
Work the diagnosis tree top to bottom, confirm endpoint values, test with curl, then run the final connection check.
Buy self-serve now, or talk with us about a larger agency inventory.