If I take a look at the generated HTML code for the tile of the "“Kiến Trúc Nội Thất MO: Sự kết hợp hoàn hảo giữa hiện…” post, I see that the background image for that tile is specifically set to the URL https://xamxi.net/wp-content/themes/pennews/images/no-thumb.jpg. Which means that your site itself thinks that this post does not have a featured image.
Can you please double check the post in the editor to make sure that the featured image was actually uploaded correctly? Given that the issue only affects this one post, my guess is that it’s this issue.
If not, then my best guess is that the issue is somewhere deep inside the code of your WordPress theme. If so, it’s your responsibility to figure that out. We just provide the hosting, it’s not up to us to fix bugs in your website.