@sampo2910 of None is the only option that works, then that's probably the only one your email provider supports. It should be fine as long as you don't need your emails to be perfectly secure.
after more problems i installed nodebb successuly finally. especially thanks to @PitaJ
after installed there was no sounds in ACP. i solved it with https://github.com/NodeBB/NodeBB/commit/759c3f5584efdaace97ae6795f48ec1755facad4
but now sounds do not play. i restarted nodebb, cleared the cache but no success.