DNS (Domain Name System) issues refer to problems with the domain name resolution process that translates human-readable domain names into IP addresses used by web servers to identify websites. DNS issues can occur due to misconfigurations, server downtime, DNS cache poisoning, or domain registrar errors. If a website experiences DNS issues, search engine crawlers like Googlebot may have difficulty accessing the site or resolving its domain name, leading to indexing problems. DNS issues can result in intermittent or complete unavailability of the website to search engines, affecting indexability and visibility in search results. To address DNS issues, webmasters should monitor DNS health using tools like DNS monitoring services or Google's DNS Checker, ensure DNS records are correctly configured and up-to-date, and contact domain registrars or hosting providers to resolve any DNS-related issues affecting website accessibility.