Can't post comments after moving blog to https

I’m currently in the middle of migrating my blog to https. I thought everything was working when today I realized that no one can leave new comments. Whether logged in (as admin) or not, everyone who tries to leave a comment on an https version of an article gets the same error:

Comment Error 

Please enter all fields correctly to post a comment.

And this even when all fields have been entered correctly.

How to reproduce:

1. Visit an https article such as 150 More Funniest Resume Mistakes, Bloopers and Blunders Ever
2. Try to leave a comment
3. You’ll get the error message above, displayed on http://jobmob.co.il/wp-comments-post.php, not the https version

However, if you leave a comment on the non-https version of the article, it works fine.

Suggestions?