PHP ftp_connect() can't establish a connection

Hi, I’m trying to establish a connection to digitalocean droplet from localhost to do ftp functions using PHP script but it is failing. Does digitalocean servers allow connecting from a remote script or i’m missing something? Your assistance will be much appreciated. See the code I’m using below:

// my ftp server $ftp_server = “159.203.186.99”;

// connect to FTP server $ftp_conn = ftp_connect($ftp_server) or die(“Could not connect”);