Discussion settings not saving

For some reason, my discussion settings aren’t saving.

I want to allow comments.

But even if I check the “Allow people to post comments on new articles” checkbox and save the settings, after a few seconds the check mark dissapears. And the comment section doesn’t appear at the bottom of my posts.

The really strange this is that the comment section appears on my very first post. But on the following ones, the comment section won’t appear.

Here’s my blog address: http://catherinerondeau.com/photographer/

Thanks in advance for your help