robots.txt file not accessible but robotss.txt is accessible

Hello,

This is really annoying, any text file in root directory of my server is accessible via URL but robots.txt is not accessible. The file is on server and when i enter url https://techposts.org/robots.txt nothing comes, not even 404 error page. But when i try access license.txt or robotss.txt, (https://techposts.org/robotss.txt) it displays the text in browser.
Can anyone please help me finding the issue.

Thanks!