Hello.
I wrote a simple webapp for a client, however, I have a rather strange problem with which I first met. The point is that a small percentage of people do not load the page. Stops on the loading animation. I turned off the gzip because I suspected that maybe it does affect but it did not help. To be sure, I have replaced all the css, font, js libraries, because maybe one of them was damaged when copying.
What else can I do to locate the error?
This looks more like a firewall issue on the clients side: maybe they are blocking websocket connections, or they are not configured to handle websocket connections.
No, that would make their firewall useless. They have to explicitely allow it. Do you use a specific port where you run your webapp on? We always make sure our apps run on port 80 and 443 (defaults http and https). For these ports, most firewalls are set to allow websockets.
Well, I know that ports 80 and 443 should be unlocked for a proxy server for websockets and such ports are set in webapp but apparently there are other filters that do not allow such connections.