RSS feed URL for post comment shows HTML source code of page
I am facing a weird issue on my site. When I type RSS feed links, global feed and comments work correctly. But, when I go on a specific post, and enter (mysiteurl.com/postname/feed), It just gives me the HTML source of that page, instead of comments feed.
I have latest WordPress 5.8. My permalink structure is working correctly. Just the post comment feed is not working.
How can it be solved ?