SMF: Approve button does not work

Using SMF 2.0.17 with CleanTalk, every time I try to click on “Approve” for an automatically blocked message, I get sent to the moderation center. (index.php?action=moderate;area=postmod;sa=approve;topic=23.0;msg=55 … )

From here I cannot find ANY way to actually approve the message. Nor does the message ever get approved, no matter what I do.

The error log, oddly enough, does not show me any errors when this happens. I can go into the message and click on Attachments and other options, and there I see “Approve this post,” but when I do this, it does not approve the post.

Any thoughts? Do I need to remove CleanTalk, approve the message, and reinstall? (This strikes me as a bad idea.)

The page I need help with: [log in to see the link]