cron jobs not working

First let me explain there are no error logs or even email notifications stating the cron job has even tried to execute.

 

Cron Job:

php /home/<private>/public_html/cron_day.php 12345678910123456789

 

The numbers at the end represent an alnum security code to keep it from being used outside of it's means.

 

Like I said, no error reports period just that the crons are not working. If I enter mysite.com/cron_day.php 12345678910123456789 into my url bar I get a 404 error. (Would explain the lack of an error log). But typing mysite.com/cron_day.php?code=12345678910123456789 works fine.

 

Thing is without any error logs how am I suppose to know what is wrong??