PHP Script Getting stopped without Any error

Hello,

I have just installed a LAMP stack. Everything is working fine. I have a PHP script that crawl web pages and fetch data through file_get_contents. I have change the max_execution_time to 9999. I run the script on my local computer and it runs fine here(It ran for 4 Hours). But on Digital Ocean the script stop after certain time. Something around 5-6 minutes. I check the Apache error_log and I cannot see any error that tell why the script has been stopped. Can you please tell if you have implemented any Limits or Anything that I missed in the configuration ?