توییتر \ @levelsio در توییتر: «If there is anything @twitter could do is make their Twitter Card robot better, it misses half the images of websites https://t.co/2Er63V7Fv6»
Twitter card image is not showing - Cards - Twitter Developers
Twitter Card Not Working: Twitterbot blocked by Robots.txt - Cards - Twitter Developers
Twitter Cardsへの登録方法
Twitter Block Web Crawlers via Robots.txt? | Web Marketing School
Issue with twitter cards ERROR: Fetching the page failed because it's denied by robots.txt - Cards - Twitter Developers