I don’t understand your permissions scheme. You have some files owned by user “www”, group “www”, others by user “nginx”, group “nginx”.
Depending on exactly how these groups are constituted, your web server (which we’re guessing operates as “nginx”, but we’re not really sure) might not be getting access to the file.
Let’s try resetting your permissions.
cd /a/domains/lms.softpowerworks.com/public_html
sudo chown -R nginx:nginx .
sudo chmod -R 755 .
sudo chmod -R 775 cache custom modules themes data upload config_override.php
Note that some of those commands end with a space followed by a dot (.)
Also, the correct line in /etc/crontab should reference the /a/domains/lms.softpowerworks.com/public_html directory, so if you had changed that, please change it back.
If that doesn’t work (it might even break your entire application), try setting things up for the other user:
sudo chown -R www:www .
then change the username in crontab from “nginx” to “www”.