Hi @umair, looks like you’re serving the site over https but the site domain has been set with just http. Have you configured the custom domain correctly?
Configuring your domain to use https will solve the facebook preview issue, as well as the other warnings that are coming up on your site. Check out our docs on setting the domain configuration: https://ghost.org/faq/change-configured-site-url/
Did you follow the instructions I linked to? There still seems to be warnings coming up, you can see them by opening the inspector in your web browser. You can also paste a link to your blog posts here to validate them for facebook url previews:
I’m afraid I can’t do that in this instance. Is there not someone with more technical knowledge that can help you with the configuration? If not then you might want to check out Ghost (Pro) where we can provide more support: