Summary Large Image : Some of the images are not shown up


I have integrated Twitter Summary Large Image.

Some of the tweets have images but some didnt show the image. The robots file of the domain from which the images are served allows "twitterbot "
There is no error on the Validator. The image sizes are larger than the minimum size , but still some of the images are not shown ?

Below is the URL which has image and all meta tags in place. But the image is not shown on twitter summard card (Image size is larger than the minimum size)

Can anyone let me know why ? Appreciate some help.

Thanks in Advance!!