Comments won't work !

Hey guys. So my comments won’t work.

https://mitomeru.net/?p=17

I try to make a test comment and press submit but instead it just leads me to a blank page with the url being https://mitomeru.net/wp-comments-post.php.

I’m currently using the Zeoal Theme. I’m not sure if it’s because the theme was not designed for this version of WordPress (which could be possible since it doesn’t look like the theme has been updated in a while). But anyways, could someone help me figure this out? Thank you so much !!