If you said X is not working, I have tried Y and Z then it’s hard for all of us to solve your problem, so try to be more specific(Include codes, Add your site Info etc).
teckingpro.com is your site, based on your username here.
This is what I have found in your site source code -
<meta property="og:image" content="http://techkingpro.com/wp-content/uploads/2017/03/TECH.jpg" />
<meta property="og:image" content="http://techkingpro.com/wp-content/uploads/2017/06/title.png" />
<meta property="og:image" content="http://techkingpro.com/wp-content/uploads/2017/04/facebook2Bhacked.jpg"/>
I don’t know how you gonna solve it, but Facebook display images when your site open graph tags points to some real images but here, your specified images return 404 (not found) error.
When you correct your images, then you can debug your URL here.