Comment fields are gone

Does your custom theme include a comments.php template file? Are you calling it using comments_template(); in single.php?

Yep that is correct: the file loop-single.php is calling it using <?php comments_template(); ?>

Does comments.php include <?php comment_form(); ?>?

Yes it does

Are you using a custom callback function in comment_form()?

Can you explain what that means. I’m not super confident in WordPress

What exactly do you have in the <?php comment_form(); ?> line?

nothing more on that line. Just <?php comment_form(); ?>

What happens if you switch to the default Twenty Eleven theme?

Then the comment box appears

Try renaming your comment.php file to something like comment-old.php

the comment.php in my own theme?

Yes.

It works now! thank you ver y much. The only thing that appears to be wrong that it says name on the email field, email on the website field etc. Where is that info located?

The problem hasn’t been solved. All you’ve done so far is narrowed down the cause of the problem to your comments.php file. I suspect there’s an error in the file that is stopping it from working correctly (if at all). Rename the file back to comments.php and turn debug on and enable error logging to try and pinpoint the exact issue.