amazon web services - Twitter card whitelisting issues probably because URL is inaccessible to crawler -

i have been trying website whitelisted twitter cards. every time apply whitelisting email saying "the url provided indiaoutside.org use summary_image_large card inaccessible."

i tried searching community , found this. apparent twitter's crawler unable access website. running aws ec2 website. how find out if aws denying access web crawler , how change that?

i not beleive aws block crawler. upto owner of instance control ports open , traffic want accept or reject - suspect having problem.

have used twitter card validator?:

https://cards-dev.twitter.com/validator

if can't pass test, not going approved twitter.