Error while logout

Hi Since I installed HIKA Shop I have I error, when I logout from the backend as administrator.
It appears only <1 second.

What does it mean?
Please see screenshot attachment

Hi Rolandus1,

In my file, there is nothing line 21 of the file hikashopuser.php.
Your website is working fine, Joomla want to achieve an action already made by our plugin, you can change your error reporting in joomla to "none" to not display this message.

SOLVED: It was a missconfiguration in .htaccess.
Now i kopied the platform in to root folder and it's OK.
Even the problem with the errors on the CSV order export is working well.