Website on whitelist but don't show card!?

[ylbert]

Please anyone can help me to know where is the problem with this website, why we can’t show the cards on link url share: https://www.osservatoriodiritti.it/ ???
Here the result on card validation:

Please help us, thanks!
Also the Yoast on this Wordpress website isn’t helping us on it !!
y.

[andypiper]

Looks like your images are inaccessible or the wrong size.

Not Whitelisted, unable to render, or no image: READ THIS FIRST

Before posting a Cards issue, please READ the following: If you are posting about any issue with your site, please include a link to the publically-accessible URL where your Card markup is visible, or we will be unable to help you. You should also make sure that you’ve checked the items below, and perform your own troubleshooting before asking for additional help. Posts that indicate that none of these checks have been performed will not be prioritised for attention. Unless you are trying to …

[ylbert]

@andypiper do you think still is wrong size?!
Because the size example recommended here: https://dev.twitter.com/cards/types/summary-large-image
like this example: meta name=“twitter:image” content=“http://graphics8.nytimes.com/images/2012/02/19/us/19whitney-span/19whitney-span-articleLarge.jpg”

Is the same on our website, with the same dimensions: 600x330px
LIKE THIS EXAMPLE: meta name=“twitter:image” content=“https://www.osservatoriodiritti.it/wp-content/uploads/2017/02/OD-card-twitter.jpg”

Why do think this images are inaccessible too?!
Help us, please!
y.

[andypiper]

Your site has a robots.txt file that blocks access to /wp-content so the images are not accessible. This is all covered in the link I pasted. Please do your own detailed debugging before asking for help. Thank you.

[ylbert]

Dear @andypiper I just changed robots.txt like this,
Allow: /wp-content
But stil the image card is not OK !
Why?!
Help us please!
y.

[ylbert]

Hi again @andypiper after few mins it start working now!!!
Thank you!!
y.

[andypiper]