In the world of cryptic and rather unhelpful error messages, “invalid json response” when trying to save & update a post or page in wordpress’ new editor runs a close second to my all time favourite “invalid shared memory realm” from Oracle’s absysmal overhyped, and overly expensive database stuff.

So what do you have to do? Simple:

o become “root”

o edit /etc/apache2/apache2.conf using the editor of your choice (nano, emacs, …)

o find the section for /var/www

o Change “AllowOverride None” to “AllowOverride All”

o make sure mod_rewrite for apache is installed and enabled (a2enmod rewrite)

o reload the apache config using systemctl reload apache2

That’s it, switching to SEO-friendly permalinks in Settings -> permalinks on your wordpress site should no longer break making changes to posts / pages and saving them.

Oh yeah, I think I left out the “what it means” part, but hey, I guess you can come up with an explanation of your own 🙂