Update the following values in /etc/php.ini:

upload_max_filesize = 20M
post_max_size = 20M

Restart php-fpm

service php-fpm restart

Add the following to the nginx http block:

client_max_body_size 20m;

Restart nginx

service nginx restart

Recently had an issue where I was unable to upload media within WordPress. Turned out the user and group in php-fpm’s www.conf was incorrect. To fix:

vim /etc/php-fpm.d/www.conf

user: nginx
group: nginx

Restart php-fpm

service php-fpm restart