enable rewrite engine in Debian:

# a2enmod rewrite

make sure the htaccess is readable – change ‚AllowOverride None’ to ‚AllowOverride All’ in configuration file of the shop website, in this case opencart shop is in dir: /var/www/shop

Options Indexes FollowSymLinks MultiViews
AllowOverride None
Order allow,deny
allow from all

TO:

Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
allow from all

then change filename .htaccess.txt to .htaccess in the dir of the shop: /var/www/shop

restart apache:
#service apache2 restart