The "connection lost" message is usually caused because the URL at which you are visiting a NodeBB forum is not the "url" value set in config.json
I can be on mangolassi.it for hours. Then I leave that tab and work in another tab for a while, and then when I click back on the tab for mangolassi.it I will be spammed with connection lost.
@psychobunny is a real superstar, but the community as a whole (users/developers) is real good one. Which is why I personally would stay with NodeBB over say Discourse, which I would say would be NodeBB's only real competitor.