Issue on custom database connection

I’m trying to connect to my SQL database using the custom database connection, but having different issues.

in my server, I have opened the port 1500 and I have also tried by specifying the port number in the connection settings as below.
options: {
database: ‘SQLDatabaseName’,
port: 1500
Now its showing the error like below,
If I remove the port 1500 from the options its connecting to the port 1433 by default, but this port is not opend.

Also, I have seen some Note(Heads up) in your site like below,

What changes I have to do in my server to allow/open the IPs/ports?