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E63 — WS_HTTP_UPGRADE_READ_FAILED

Reading the HTTP 101 Upgrade response from the FKMTime server returned 0 bytes.

What happens​

The error is logged once per boot, ws_loop returns an error, and the outer ws_task loop waits 500 ms before calling ws_loop again. The device retries the connection automatically.

Possible causes​

  • The server closed the TCP connection immediately, possibly because the request path, version query parameters, or authentication did not match what the server expects.
  • The server is running but not at the path the device is connecting to (version mismatch between device firmware and server).
  • A firewall, reverse proxy, or load balancer is terminating the connection before the server sees it.

How to fix​

  1. Check server and firmware versions — Ensure the FKMTime server and device firmware are on compatible versions.
  2. Check server logs — Look for rejected connection attempts around the time this error occurred.
  3. Check network path — If a reverse proxy is in use, ensure it passes WebSocket upgrade requests through without terminating them.
  4. Wait — The device retries automatically. If the server was momentarily restarting, it will reconnect once the server is back.