I see the whole page is collapsed but I see the same issue on your other standard WordPress pages too. When inspecting the issue, I see that the CSS and JS files are using the wrong URL.
Example:
https://wwww.tsarr.in/wp-content/cache/min/1/wp-content/themes/twentytwentyone/style.css?ver=1665910211
This is most likely a misconfiguration issue related to your caching plugin. As a quick solution, kindly clear your site cache. Then, investigate your caching plugin settings and re-configure it correctly.
Regarding the 404 error,
Kindly refer to the “Notes” section on our “Getting Started” tutorial here https://plugins360.com/all-in-one-video-gallery/documentation/
During the plugin installation, we create several pages dynamically on your website. The “Player Embed” page is one of those pages and this is the page that is used as an Iframe URL when embedding our player.
It shows that you have deleted the “Player Embed” page added by our plugin and this is the reason for the issue.
Solution #1:
Kindly go to the “Video Gallery => Settings” menu from your WordPress Admin Dashboard and change the “Player Type” to “JavaScript”, save the changes and check now.
Solution #2:
Go to the “Video Gallery => Dashboard => Issues Found (tab)” from your WordPress Admin Dashboard and click the “Apply Fix” button. This will reconfigure the deleted/edited pages.
Hope this helped you!