@Sungjun_Na this appears to be resolved?
@nathanmartin I’m not sure what the issue was in this case as it was already solved, but if someone has correctly added Netlify nameservers (and they’re not running into [Support Guide] How to detect and fix inactive Netlify DNS zones), then it’s almost always the case where the DNS Records were added to Netlify’s Database, but not added to NS1 (our DNS provider). We usually manually add it there, or the user can fix it by removing the domain from site settings and adding it back as that will remove the records from our database and re-add it.