I have inherited a Symphony site and I get the following error,
Fatal error: Uncaught exception 'RuntimeException' with message 'Failed to write cache file "/var/www/html/app/cache/prod/classes.php".' in /var/www/html/vendor/symfony/symfony/src/Symfony/Component/ClassLoader/ClassCollectionLoader.php:239
I did a chmod -R 777 cache but with no luck. The classes.php file does not exist.
If you are linux user then you need to fire below listed command:
HTTPDUSER=`ps axo user,comm | grep -E '[a]pache|[h]ttpd|[_]www|[w]ww-data|[n]ginx' | grep -v root | head -1 | cut -d\ -f1`
sudo setfacl -R -m u:"$HTTPDUSER":rwX -m u:`whoami`:rwX var
sudo setfacl -dR -m u:"$HTTPDUSER":rwX -m u:`whoami`:rwX var