Warning: Undefined variable $conn in C:\wamp64\www\Evantage_api\update_password_poclicy.php on line 17

Fatal error: Uncaught TypeError: sqlsrv_query(): Argument #1 ($conn) must be of type resource, null given in C:\wamp64\www\Evantage_api\update_password_poclicy.php:17 Stack trace: #0 C:\wamp64\www\Evantage_api\update_password_poclicy.php(17): sqlsrv_query(NULL, 'update pwd_set ...') #1 {main} thrown in C:\wamp64\www\Evantage_api\update_password_poclicy.php on line 17