I have a mobile app that people can share a link to it on Facebook and it's has been fine for months. But in the last few days, when people share the short dynamic (deep) link that is configured in Firebase dynamic links, Facebook says it goes against community standards.
However, if I post the long deep link (not the short) on Facebook, it works fine. I used the Facebook share debugger to see what could be the problem. If I put the short deep link, it says "the website contains a blocked URL" and nothing more (no other info or meta data). Even though, the links that the deep link converts to are the app on play and app store, and for the web it's the web page that shows a description of the app and has been the same all the time while the share was working fine (the web page url only shows a warning to include some missing properties in page and not a blocked URL on Facebook share debugger, same message as with working long dynamic link).
So how can I figure out the real problem? Many thanks.
Found the problem. It was the image preview URL in the dynamic link. For some reason, the hosted link was considered as a suspicious URL even though in was hosted on a trusted site and works on other platforms.