The newest openhabian release causes Frontail 4.9.1 to not being able to display any logs. On web console the fault message can be seen:

index.js:83 WebSocket connection to 'ws://192.168.0.51:9001/socket.io/?EIO=3&transport=websocket' failed: Error during WebSocket handshake: Unexpected response code: 400

As a workaround, editing web/index.html and changing transports: ['websocket'] to transports: ['polling'] makes it workable again or alternatively, downgrading to 4.9.0.

Any idea what the real cause could be for this error message?