Intellij Idea - "gradle project sync failed" in Android project

Press "Refresh all Gradle projects" in View > Tool Windows > Gradle

CKEditor + Symfony - Cannot read property 'icons'

Be sure in config.yml in "extraPlugins" plugin name is the same as in specified plugin's file plugin.js first row, for example: "CKEDITOR.plugins.add( 'filepreview', {", where 'filepreview' is config.yml's plugin name.

Sonata-Media PublicDownloadStrategy not working in Prod environment

After changing config.yml file, do not forget to clear prod cache (app/console cache:clear -e prod)