Permissions and owner of var/cache/* are correct. PS 1.7.6.1, PHP7.2/Apache 2.4
Often got white screen and this error in httpd.log when hit "Clean Cache" button at website backend. Refreshing the page will help to continue to green "Cache cleared successfully" message. Unable to find what causing this. Prestashop debug mode showing no errors. Please help.
[proxy_fcgi:error] [client xx.xx.xx.xx:56464] AH01071: Got error 'PHP message: PHP Fatal error: require(): Failed opening required '/var/public_html/var/cache/dev/Containerxxxxxxx/getPrestashop_Core_Admin_PagePreferenceInterfaceService.php' (include_path='/var/public_html/vendor/pear/pear_exception:/var/public_html/vendor/pear/console_getopt:/var/public_html/vendor/pear/pear-core-minimal/src:/var/public_html/vendor/pear/archive_tar:.:/usr/local/share/pear') in /var/public_html/var/cache/dev/Containerxxxxxxx/appDevDebugProjectContainer.php on line 1708\nPHP message: PHP Fatal error: require(): Failed opening required '/var/public_html/data/var/cache/dev/Containerxxxxxxx/getDebug_FileLinkFormatter_UrlFormatService.php' (include_path='/var/public_html/vendor/pear/pear_exception: /var/public_html/vendor/pear/console_getopt: /var/public_html/vendor/pear/pear-core-minimal/src:/var/public_html/vendor/pear/archive_tar:.:/usr/local/share/pear') in /var/public_html/var/cache/dev/Containerxxxxxxx/appDevDebugProjectContainer.php on line 1708\n', referer: https://mywebsite.com//adminxxxxxxxxxx/index.php/configure/advanced/performance/?_token=xxxxxxxxxxxxxxxxxxxxxxxx