FAQ snippets may fail to expand due to missing or improperly implemented FAQPage schema. Ensure you are using JSON-LD or Microdata with properly nested questions and answers under the @type: FAQPage schema.
Each question should be clearly defined with <h3> or <h4> tags, and answers should be complete yet concise. Ensure that both questions and answers are visible in the page content, as hidden FAQ data can lead to penalties or exclusion from rich results.
Avoid keyword stuffing, as search engines favor natural language. Additionally, check Search Console for structured data errors and ensure the page is indexable.
For better results, test your schema using the Rich Results Test and consider linking to relevant internal pages within the answers for better engagement.