First start with logging into your box:
Then like @ScottA mentioned call your script: This time do it with verbose flag which is -x.
sh -x /var/www/html/pllsrv2313.dev/scripts/script_name.sh
This is going to dump out everything your script runs or error out. See if anything is not what you expected.
In my case Inside my script I had a curl request that was not going through as planned:
curl --silent --compressed http://dev.example.com/code.sh
So I flagged my curl call --verbose to get that to dump as well:
curl --silent --compressed --verbose http://dev.example.com/
and called:
sh -x /var/www/html/example.dev/docroot/ex_scripts/my_script.sh
I got back that the host could not be resolved because my dev domain was only available inside my DNS. So for me the problem is when cron runs my curl fails do to my non public accessible dev domain.
...
+ curl --silent --compressed --verbose http://dev.example.com/
* getaddrinfo(3) failed for dev.example.com:80
* Couldn't resolve host 'dev.example.com'
* Closing connection #0
...