Your forum may work, but has no security, anyone can login and delete/steal the database. You need to setup your redis so that it has a password, and that it restricts access to localhost.
@yariplus thank you so much.
My forum was running ok but last night suddenly it start showing 502 bad gateway.
I was looking for issue but after 5min soon I started nodebb from terminal, it started working. But again it started showing the same 502 bad gateway error.
502 bad gateway is the error that nginx returns when NodeBB isn't running. Try running NodeBB will
./nodebb slog or
./nodebb dev and look for errors. Odds are that it is encountering an error and dying.