Hello Jiokrish,
Thanks for reaching out regarding your media thumbnail.
To resolve this, we would first recommend checking your page’s link using Facebook’s Sharing Debugger tool located at https://developers.facebook.com/tools/debug/sharing/. Can you please try running the Facebook Sharing Debugger on the page you are experiencing the issue on, and under ‘When and how we last scraped the URL’ clicking the ‘Scrape Again’ option and letting us know whether this resolves the issue? The ‘Scrape Again’ option will force Facebook to update its cache for your page’s link.
Please note that to successfully update the cache, it may require re-scraping your page several times as whether the page’s data can be read may take several requests between Facebook and the server your website is hosted on. Also, this guide includes more information on this and explains in detail how to do this: https://kb.yoast.com/kb/facebook-sharing-updated-details/