Getting error Please wait and Connection error 0

I have made a application for one customer where i am getting very annoying issue.

We have made the streamlit app and deployed on customer server. It is accessible through VPN network. When I am accessing the application in his network through VPN it is working fine but it is not working from customer PC even both are in same network. I have cleared is all caches still getting the error Please wait and after some time it is giving connection error.

There might be some network firewall or settings restricting the app connection on the customer’s PC. I would verify the network settings are good and all the required ports are open and accessible.