htaccess dosyanızın çeriginiz aşağıdaki ile degiştirin sorununuz çözülecektir.. ancak bu kod bazı sunucularda sonsuz döngüye sebeb oluyor ve ip engllemesi yapılabiliyor deneyin öyle bir sorun yşarsanız kaldırırsınız yaşamazsanız sıkıntısız kullanabilirsiniz bir çok sitede ve hatta kendi https://www.opencart-themes.org sitemde de kullandıgım bir koddur.. yapmadan önce benim sitemden kontrol edebilirsiniz.. muhtemeln kodu yanlış satıra eklediginiz için yaşıyorsunuz..

  # 1.To use URL Alias you need to be running apache with mod_rewrite enabled.
  # 2. In your opencart directory rename htaccess.txt to .htaccess.
  # For any support issues please visit: http://www.opencart.com
  # Options +FollowSymlinks
  # Prevent Directoy listing
Options -Indexes
  # Prevent Direct Access to files
#<FilesMatch "(?i)((.tpl|.ini|.log|(?<!robots).txt))">
<FilesMatch "(?i)((.tpl|.ini|.log))">
 Order deny,allow
 Deny from all
</FilesMatch>
  # SEO URL Settings
RewriteEngine On
# If your opencart installation does not run on the main web folder make sure you folder it does run in ie. / becomes /shop/
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R,L]
RewriteBase /
RewriteRule ^sitemap.xml$ index.php?route=feed/google_sitemap [L]
RewriteRule ^googlebase.xml$ index.php?route=feed/google_base [L]
RewriteRule ^system/download/(.*) index.php?route=error/not_found [L]
RewriteCond %{HTTP_HOST} ^(?!www.)(.+) [NC]
RewriteRule ^(.*) https://www.%1/$1 [R=301,NE,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !.*.(ico|gif|jpg|jpeg|png|js|css)
RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]
  ### Additional Settings that may need to be enabled for some servers
### Uncomment the commands by removing the # sign in front of it.
### If you get an "Internal Server Error 500" after enabling any of the following settings, restore the # as this means your host doesn't allow that.
  # 1. If your cart only allows you to add one item at a time, it is possible register_globals is on. This may work to disable it:
# php_flag register_globals off
  # 2. If your cart has magic quotes enabled, This may work to disable it:
# php_flag magic_quotes_gpc Off
  # 3. Set max upload file size. Most hosts will limit this and not allow it to be overridden but you can try
# php_value upload_max_filesize 999M
  # 4. set max post size. uncomment this line if you have a lot of product options or are getting errors where forms are not saving all fields
# php_value post_max_size 999M
  # 5. set max time script can take. uncomment this line if you have a lot of product options or are getting errors where forms are not saving all fields
# php_value max_execution_time 200
  # 6. set max time for input to be recieved. Uncomment this line if you have a lot of product options or are getting errors where forms are not saving all fields
# php_value max_input_time 200
  # 7. disable open_basedir limitations
# php_admin_value open_basedir none