- First, make sure that your MySQL server service is running on the host. Restart the service\deamon for good measure.
- Make sure the inbound firewall rules are set to allow access to that service on the host.
- Make sure that the host and the client are on the same subnet, that you can ping one from the other assuming that they are both setup to respond etc.
- Make sure the outbound rules on the client are set to allow your application to reach out on that port.