Panel Dashboard Running in Ubuntu Virtual Machine 'Not sending notification back to client for Change it Requested'


I have developed a panel based dashboard. The machine I have used to develop it is a windows machine. I have been developing the dashboard using a jupyter lab notebook. On this personal machine I am able to add ‘template.servable()’ a the end of the notebook – and then deploy the notebook using panel serve from the command line. When I do this, other users who have access to the local network can login to the dashboard while it is running on my desktop and have their own session state.

However, if I move the .ipynb file to a dedicated server running a ubuntu virtual machine and deploy it – when I then try to connect/login to the dashboard I am getting the error message below. What is happening is that anytime the backend/server needs to send data back to (even a single) client instance it is sending nothing (so the client facing website appears nonresponsive). This is strange because it is clear from the debug logs that the server side does receive input from the client, it just won’t send any messages back.

I am not entirely sure if this is an issue with: virtual machine, network firewall, panel framework, my code, or linux vs windows environment…

If you have any thoughts or have seen this error before that would be appreciated. Thanks.

2021-06-02 20:26:14,701 Not sending notification back to client <bokeh.server.connection.ServerConnection object at 0x7f96d20d6400> for a change it requested
2021-06-02 20:26:14,704 Patching attribute ‘hover_data’ of PlotlyPlot(id=‘1041’, …) with {‘points’: [{‘curveNumber’: 0, ‘x’: 483, ‘y’: 389, ‘color’: [242, 239, 233, 1], ‘colormodel’: ‘rgba256’, ‘z’: [242, 239, 233, 1]}]}

Hi @Mward97

Welcome to the community.

Is it possible to provide the notebook and some screenshots? More information is probably needed to identify the root cause and the solution.


Hi Marc @Marc ,

Thank you for your response. This issue was resolved, and had nothing to do with panel. There was an internal network permissions issue that’s error message was being suppressed by my panel script for some reason.

Thank you

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