Php/mySQL connection to remote server, fatal error, connection timeout

I’ve got one droplet at DO and one webspace with domain at another hosting provider. I don’t have access to anything other than ftp on the other server. On that other webspace I’ve got a php script which I want to remotely connect to my mySQL db on my droplet. I’ve opened the port 3306 in the firewall, added a user with access to the table from % and changed the row starting with “bind-adress” (also tried commenting out) in the configuration file. Still I get an error like this when trying to connect:

Fatal error: Uncaught exception ‘PDOException’ with message ‘SQLSTATE[HY000] [2002] Connection timed out’ in {the url to the script that’s trying to connect}:19 Stack trace: #0 {the url to the script that’s trying to connect}(19): PDO->__construct('mysql:host={my droplet public ip}, ‘{username}’, ‘{password}’) #1 {main} thrown in {the url to the script that’s trying to connect} on line 19

And the connection part in php looks like this:

$db = new PDO(‘mysql:host={droplet public ip};port=3306;dbname={database name};charset=utf8’, ‘{username}’, ‘{password}’);

What am I doing wrong?! I’ve contacted the DO support, they couldn’t help me since we don’t know where the problem is. They told me to try the community.