This question could be all around but I have tried most answers and permission 777. But, still no luck.
/etc/apache2/sites-available/mysite.conf
<VirtualHost *:80>
ServerName www.mysite.com
ServerAdmin mymail@mail.com
DocumentRoot /var/www/html/wordpress
ErrorLog ${APACHE_LOG_DIR}/mysite_error.log
CustomLog ${APACHE_LOG_DIR}/mysite.log combined
</VirtualHost>
/etc/vsftpd.conf
listen=YES
anonymous_enable=NO
local_enable=YES
write_enable=YES
dirmessage_enable=YES
use_localtime=YES
xferlog_enable=YES
connect_from_port_20=YES
chroot_local_user=YES
secure_chroot_dir=/var/run/vsftpd/empty
pam_service_name=vsftpd
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
rsa_private_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
allow_writeable_chroot=YES
I set permission 777
to /usr/share/wordpress
and /var/lib/wordpress
.