This section is about common Drupal error & how to fix it.. It is potentially insecure to display oEmbed content in a frame that is served from the same domain as your main Drupal site, as this may allow execution of third-party code Database Isolation Level REPEATABLE-READ Entity/field definitions Mismatched entity and/or field definitions Entity/field definitions Mismatched entity and/or field definitions File system Not writable File system Writable (public download method) Font Awesome IconPicker Not installed PHP OPcode caching Not enabled Page not found The requested page could not be found Private files directory Not fully protected Root composer.json requires drupal/.., found drupal/.. SSL certificate problem: unable to get local issuer certificate State cache flag not set Temporary files directory Not fully protected The website encountered an unexpected error. Please try again later Trusted Host Settings Not enabled Webform: Private files Private file system is not set Your requirements could not be resolved to an installable set of packages Book traversal links for Drupal error & how to fix It is potentially insecure to display oEmbed content in a frame that is served from the same domain as your main Drupal site, as this may allow execution of third-party code