After clean cache [Advanced Parameters -> Performance] from prestashop backend we got this error PrestaShop

[yusufraza]

hello all
i am using prestashop 1.7.5.0 some page given error 500
then am clear cache from admin>administrator>performance>catche >clear all

then I got a blank page

then I remove/var/cache/dev or prod directory but the problem still the same.

thanks in advance.

Fatal error: Uncaught Error: Class 'Db' not found in /opt/bitnami/apps/prestashop/htdocs/config/alias.php:48 Stack trace: #0 /opt/bitnami/apps/prestashop/htdocs/config/alias.php(53): pSQL('configuration') #1 /opt/bitnami/apps/prestashop/htdocs/classes/Configuration.php(155): bqSQL('configuration') #2 /opt/bitnami/apps/prestashop/htdocs/classes/Configuration.php(209): ConfigurationCore::loadConfiguration() #3 /opt/bitnami/apps/prestashop/htdocs/classes/PrestaShopAutoload.php(171): ConfigurationCore::get('PS_DISABLE_OVER...') #4 /opt/bitnami/apps/prestashop/htdocs/classes/PrestaShopAutoload.php(130): PrestaShopAutoload->generateIndex() #5 [internal function]: PrestaShopAutoload->load('Db') #6 /opt/bitnami/apps/prestashop/htdocs/config/alias.php(48): spl_autoload_call('Db') #7 /opt/bitnami/apps/prestashop/htdocs/config/alias.php(53): pSQL('configuration') #8 /opt/bitnami/apps/prestashop/htdocs/classes/Configuration.php(155): bqSQL('configuration') #9 /opt/bitnami/apps/prestashop/htdocs/classes/Configuration.php(209): Configu in /opt/bitnami/apps/prestashop/htdocs/config/alias.php on line 48

[Rhobur]

Are you sure you have the Db.php located in classes/db and it is owned by the apache/nginx user having 0644 as permissionss?