Uninstall FreePBX completely

Sorry, I can’t reproduce it. Did you check owner and permissions of /var/www/html/freepbx?

[root@testserver ~]# ls -l /var/www/html
total 8
drwxrwxr-x 3 asterisk asterisk   54 Oct 10 21:44 freepbx

You are absolutely right. Reinstallation should work better in your case but I’d like to know why it doesn’t work so we can improve Nethserver.

Could you post relevant error messages in /var/log/messages after trying to install/remove?