I got this message from Card Validator when I review my URL (http://www.chattyplay.com/) in that tool.
Of cause my URL is opened already and can access freely from internet.
INFO: Page fetched successfully
INFO: 13 metatags were found
INFO: twitter:card = app tag found
ERROR: Required meta tag missing (twitter:text:title)
WARN: Not whitelisted
But about “ERROR: Required meta tag missing (twitter:text:title)” this meta tag not required for “App card” I guess and Can’t resolve this “WARN: Not whitelisted”.
Would you have any help about this?