So I encountered that my website’s content is not sharable on Linkedin, even though it was sharable two weeks ago 
And here is why:
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You need to make sure that each page of your website has proper tags aligned with LinkedIn Read more Here
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Even when you do so, your website’s pages will not be discoverable by Linkedin yet, I assume because Linkedin didn’t crawl your website again… again, so what you need is to either wait or educate your users to inspect their pages (in case it is pages belong to your users like in my case “their projects”) , and I mean by inspect is to “sort of” force Linkedin to crawl that page
in order to do so, you need to go to Linkedin Post inspector’s page, then copy and paste the page’s URL that you want LinkedIn to see, and press inspect, be aware that not always this will work from the 1st time, you may need to refresh the inspector’s page and paste the URL once again
Here is a quick video on how I did that on my website.
Hope that was helpful 