Comments up and running again
Sometimes, website administration is the kind of chore I abhor. This sort of feeling takes over when bad code breaks good code. The job is much easier when my visitors alert me to a problem! Thank you Herm for telling me when the commenting feature is broken!
The error looks like this:
The solution is to remove some offending code from the .htaccess file in the site’s root folder. Any number of security-related and WordPress-hardening plugins add this code to the .htaccess file. The one I use is called Wp htaccess Control, and it has an option for “hardening WordPress comments” located in its settings under “suggestions.” Unchecking that feature fixes the issue.
Other plugins may require you to edit the .htaccess file manually. Look for these lines of code and comment them out. If your Jetpack comments cease working later on after making this change, look to the .htaccess file again. It’s likely because a plugin update or a new plugin has ruined your day.