fix permission
I prefer to own all the directories and files (it makes working with everything much easier), so I do:
## Webserver as owner (the way most people do it):
sudo chown -R www-data:www-data /path/to/your/wordpress/root/directory
#Assuming `www-data` is your webserver user.
sudo usermod -a -G www-data ubuntu
sudo chown -R my-user:www-data /path/to/your/wordpress/root/directory
sudo chgrp www-data /var/www/html/wordpress/wp-config.php
sudo chmod 660 /var/www/html/wordpress/wp-config.php
#Then I give both myself and the webserver permissions:
sudo find /path/to/your/wordpress/root/directory -type f -exec chmod 644 {} \;
sudo find /path/to/your/wordpress/root/directory -type d -exec chmod 755 {} \;
sudo find /var/www/html/wordpress/wp-content -exec chgrp www-data {} \;
sudo find /var/www/html/wordpress/wp-content -type d -exec chmod 775 {} \;
sudo find /var/www/html/wordpress/wp-content -type f -exec chmod 664 {} \;
## Step 5: privatize wp-content
echo '::STEP 5/5:: Privatize /wp-content (Set 755)'
sudo chmod 755 /var/www/html/wordpress/wp-content