Sometimes people face problem while sharing links on Facebook, when we share links on Facebook in preview we see, sometimes image is missing or sometimes preview image, title and description text, all three are not appearing instead URL only showing (as seen in below screenshot).
And if you share links like this on your Facebook profile or Pages it won’t look good, doesn’t attract people and also decrease user interaction. So to solve this problem you need to make sure that Facebook can read your page’s (page’s URL you are going share) meta data correctly. To check, visit Facebook URL Debugger/Linter, there give your webpage URL and click on Debug button
Then it will show you all the meta data which it got from your webpage, which Facebook uses to display snippet from your page. If there will be any error in your meta data or any important meta data is missing it will show you all the errors and warnings. And you can also view the code which Facebook crawler read from your webpage by click on See exactly what our scraper sees for your URL at the bottom of Object Debugger page.
Now if you find that title, image and description is appearing correctly in Facebook Object Debugger page then again try to share it on your Facebook Profile or Pages and you will find it is appearing correctly. If it isn’t appearing correctly then re-debug that webpage and share it after few minutes.
This problem appears because Facebook crawler crawls every pages once a day so if you made any changes or posted anything new on your webpage which Facebook didn’t crawled it till now so it will not show preview correctly while sharing.
If it showing any error or warning in your page then it is because any or some of the Open Graph (og) meta tags is/are missing from your webpage. To know more about Open Graph meta tags read here.