When does "Sec-WebSocket-Accept not found" occur?

[Jay_EEE]

I reset about 500 ESP32E and ESP32D at the same time.

About 480 ESP32s were connected to the server normally, but about 10 to 20 ESP32s were unable to connect to the server for about 20 minutes.

The ESP32s in question even succeeded in downloading data over an http connection, and then failed to connect to the websocket.

Code: Select all

[0;31mE (10512) TRANSPORT_WS: Sec-WebSocket-Accept not found[0m

[0;31mE (10512) WEBSOCKET_CLIENT: Error transport connect[0m

[0;32mI (10516) WEBSOCKET_CLIENT: Reconnect after 10000 ms[0m

When does the above error occur?