If you are having trouble connecting to your database, check your config file to make sure the port and bind-address have been set.

Example Config:

/etc/mysql/my.cnf
port = 3306
bind-address           = 127.0.0.1 localhost
#bind-address           = 159.203.5.166 external

In this example, the localhost bind-address is not commented out so it will be used as the db.host value in the POST /instance configuration. The port is set to 3306. In this case when you authenticate a connector instance, use 127.0.0.1:3306 as the value for db.host.

If you want to expose the external bind-address, then comment out the localhost bind-address.

If you want to expose both sources (localhost and external), then comment out both addresses.