I am trying to install Drupal 7 in a VirtualBox running Ubuntu, used Vagrant to set up the VirtualBox.
On the third step of the installation I got an error
File system The directory sites/default/files is not writable. An automated attempt to create this directory failed, possibly due to a permissions problem. To proceed with the installation, either create the directory and modify its permissions manually or ensure that the installer has the permissions to create it automatically. For more information, see INSTALL.txt or the online handbook.
I have read and followed the instructions here
I already executed the commands below
chmod a+w sites/default/settings.php chmod a+w sites/default
So as a last resort I created the sites/default/files directory manually
mkdir files chmod 777 files
But I still get the same error message after changing the permissions on the folder