Usually, when your Mesos Master is behind a reverse proxy/LB; the keepalive timeout value would be set to a small value e.g., 60 seconds for nginx. This results in the persistent connection between the browser and the Mesos master breaking resulting in the connection lost dialog (see attached screenshot). This is very inconvenient when debugging using the Web UI.
We should consider making the error dialog less intrusive e.g., update an element to signify that a reconnection is in progress similar to what other online services like gmail etc. do.