Cron没有执行文件

I have a php file to execute every minute but when I am running it on command line it executes as expected, but when set to cron job it does not run. Below mentioned are things which I have checked:

  1. cron service
service crond status
crond (pid  183872) is running...
  1. Checked logs of cron execution :
May 21 00:27:01 spartans CROND[194123]: (root) CMD (/usr/bin/php  /home/dev/my.php)
May 21 00:27:01 e2e CROND[194122]: (root) MAIL (mailed 84 bytes of output but got status 0x004b#012)
  1. CronJob list in crontab -e
*/1 * * * *  /usr/bin/php /home/dev/my.php

My request is to help me in finding error where things are getting wrong. I have started cron service couple of times.