What is the *mostcritical error reported in Naver Webmaster Tools that requires immediate attention to prevent significant ranking drops?

The most critical error is a sudden and substantial increase in crawl errors, particularly 404 (Not Found) errors or 5xx (Server Error) errors. This indicates that Naverbot, the Naver search engine crawler, is unable to access important pages on your website. When Naverbot cannot crawl and index your content, those pages will be removed from Naver's index, leading to a significant drop in search rankings and organic traffic. A large number of 404 errors typically indicates broken links or missing pages, while 5xx errors suggest server-side issues preventing Naverbot from accessing the website. Addressing these crawl errors immediately is crucial to ensure that Naverbot can properly crawl and index your website, preserving your search rankings and organic traffic.