I've recently upgraded Symfony to the new Symfony4.1. As seen over here we no longer need to setup file permissions anymore. I ran the command:
php bin/console cache:warmup
And no errors came while running that. However when I try and view the website. I get the following error.
Uncaught RuntimeException: Unable to write in the cache directory (/var/www/mywebsite.com/var/cache/prod)
in /var/www/mywebsite.com/var/bootstrap.php.cache
Obviously this means that the new feature of Symfony4.1 is not working for me. Any idea what might be causing this?