I'm getting this error:
406 Not Acceptable
An appropriate representation of the requested resource /admin/define_pages_editor.php could not be found on this server.

I started off by uploading a define_shippinginfo.php page into my custom folder. I then realised I needed to make a minor change, so I used the Define Pages Editor and saved the change. Well and good.

I then uploaded define_conditions.php into my custom folder. On attempting to do the same kind of edit with the Define Pages Editor, I got this 406 error message when trying to save. I tried another file, the define_privacy.php page, same error.

What could have happened in the space of 10 minutes?

I tried re-uploading the define_pages_editor.php file but that hasn't helped.