I'm grasping for straws here but this problem:
https://www.kunena.org/forum/kunena-support-reporting-defects/137228-kunena-not-attaching-uploaded-attachment-file
is driving me crazy. As it says I've tried disabling Admin Tools created htaccess-file and replaced it with the Joomla original one. I just tried disabling everything under WEF / Active Request FIltering and Project Honeypot but still no luck. Is there any other way Admin Tools could block attaching an image to a Kunena forum message?
Basically I'm looking for confirmation that this problem is not due to Admin Tools so I can move on to other less likely Joomla addons.