Structured data, also known as schema markup, is a standardized format for providing additional context and metadata about web content to search engines. It helps search engines understand the content and purpose of a webpage, leading to enhanced search results such as rich snippets, knowledge panels, and carousel listings. However, structured data errors can cause indexing problems if the markup is incorrect, incomplete, or violates Google's structured data guidelines. Search engines may ignore or misinterpret structured data with errors, leading to reduced visibility of rich snippets and other enhanced search features. To address structured data errors, webmasters should use Google's Structured Data Testing Tool to validate markup, fix any errors or warnings reported by the tool, and adhere to Google's structured data guidelines and best practices. They can also monitor search appearance and performance in Google Search Console for rich snippets and other structured data features.