MiMe Type Error: ComFy Magazine

Good Day!

Could you please check my website at

• https://www.onepieceoverdose.co.cc

. If you would see the theme is not loading properly and if you would take a look at Firefox error you would see this:

Error: The stylesheet https://atbhost.net/error/500.shtml was not loaded because its MIME type, "text/html", is not "text/css".
Source File: https://onepieceoverdose.co.cc/wp-content/themes/comfy/style.css
Line: 0

What is wrong? And What should I do?
I really love this theme.

(BTW I used a different host server and installed it there the theme was working but with my new host it was not working)