HTTP error 500 showing

Now ,It is showing like this
Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /home/u312208110/domains/darulfalah.in/public_html/accounts/includes/db_connect.php:7 Stack trace: #0 /home/u312208110/domains/darulfalah.in/public_html/accounts/system_load.php(4): include() #1 /home/u312208110/domains/darulfalah.in/public_html/accounts/login.php(2): include('/home/u31220811...') #2 {main} thrown in /home/u312208110/domains/darulfalah.in/public_html/accounts/includes/db_connect.php on line 7

Hey this script have been removed from CodeCanyon and no more is supported. The error you are getting is because you are using latest PHP version which this script doesn't support. 

Kindly downgrade your php version to 5.6 for this script's folder to run .