Twitter card not whitelisted because URL is "inaccessible"

[AltvrApps]

Hi,
I’ve submitted the link twice for twitter card whitelisted and it was rejected both times because it is “inaccessible”. But as far as I can tell, there should be nothing keeping it from being accessible. I’ve had a number of people check and they can all access it.

This is the link I submitted:

Photo by bobobo | AltspaceVR

And this is the response I got:
“The URL you provided for account.altvr.com to use the summary_with_large_image card is inaccessible. Please check to make sure the page is available, then reapply for a Twitter card.”

Can I get some more information about what is “inaccessible”? I can’t find any problems to address.

[rchoi]

https://account.altvr.com/photos/142080162693907014

There are a couple of reasons this might fail, detailed on our troubleshooting page.

https://dev.twitter.com/cards/troubleshooting

In particular, I would look at this part:

Your web host may be blocking web crawler access to your site. You should contact your hosting provider and ask them to ensure they are not blocking Twitter access by either IP or ASNUM. The following are Twitter’s IPs:
199.59.148.209
199.59.148.210
199.59.148.211
199.16.156.124
199.16.156.125
199.16.156.126
Also, Twitter’s ASNUM is AS13414.

[rchoi]

summary_with_large_image

Should be summary_large_image

[rchoi]