Sorry for raising this topic again. This thread is closest to what I experience among all "Connection Lost" threads in this forum.
RPi --- Proxy --- PC
\ \-- Tablet
As presented in the chart above, Node-RED Dashboard can be accessed from devices inside the LAN, or from the Internet via reverse proxy.
Connecting with PC works always both ways.
Connecting with Android based cellphone (samsung) works always from LAN, and almost always via the Proxy.
Connecting with cheap Android tablet works always from LAN, and rarely via the Proxy.
When not connecting, the "Connection lost" pop up appears on the screen, and repeating endlessly.
Proposed here solution with Chrome flags doesn't work: in modern Chrome there are not such flags on all types of devices.
In parallel thread it was recommended to reduce number of charts, controls, and data in the dashboard. This makes no sense to me: the Dashboard exists for rich content to be presented.
Maybe the "Connection lost" pop up appears due to some kind of timeout?
If so, how the timeout can be prolonged, letting the page more time to load?