When sharing a URL on LinkedIn, you may find that the share box does not display the Open Graph image and text as it should — simply showing a grey image with the website’s domain name instead. It appears that LinkedIn’s crawler is having problems connecting to some shared URLs — this could be a network issue within LinkedIn’s network, their network provider(s), and/or a bug with their crawler. LinkedIn is aware of the issue and their response on 2015/03/16 was:
I heard back from my research team and they were able to isolate the issue. Our engineering team is working on it but there’s no estimate as to how long that might take. We’ll do our best to keep you posted.