Slickalpha NS Checker tool validates nameserver entries from public DNS cache against authoritative nameservers presented by domain registry.
If public nameservers are empty, and it has been 72 hours since last change, authoritative nameservers may not be resolving your DNS queries. This can be fixed by contacting the DNS hosting provider indicated on "Registered nameservers".
If authoritative nameservers (WHOIS nameservers) are empty, it may indicate an expired domain or other domain system errors. This may be checked by confirming the domain validity and its nameservers on the domain registrar platform where the domain was purchased.
Lack of matching records may break DNS resolution. Websites and other internet properties relying on DNS resolution may become unreachable.