Unable to get connect with MySql server

I created my workflow and tried to get connect to the MySql database for that first I installed the Sql plugin then I had created my own MySql connection string according to syntax which was provided on the Bubble Academy. Now, here I came across an issue as when it tries to get connected with the database within some time connection get’s time out.
NOTE:- database is secured with a VPN and uses an Authorisation App for that.