(and many others of my forum-sites!)
Sorry for my bad english:
For a long time “Twitter card” worked perfectly with my Website! Suddenly, since a few days ago, tweets from my website to Twitter shows no card/pic and stopped working. So I testet with Card Validator. It shows an error:
INFO: Page fetched successfully
WARN: No metatags found
Next I testet as suggested with “Curl -A Twitterbot (URL)” and all Twitter-metatags are visible. The source code of the website has not been changed, since Twitter Card worked without any problems.
I tried the troubleshooting steps already!
Thanks in advance for your help and suggestions.