Connecting to AWS RDS PostgreSQL Database Failed

I am new to AWS and backend development. I failed to connect an AWS online database using node-postgres with the code below.

const { Client } = require('pg');

const client = new Client({
  host: 'database-1.*****.us-east-1.rds.amazonaws.com',
  port: 5432,
  user: 'postgres',
  password: '<master-password>',
  database: 'postgres'
});

The error message I got was connect ECONNREFUSED, and I am not sure what each parameter (host, port, user, password, database) for initializing the client object corresponds to. By the way, here is some information I retrieved in the cloudshell.

[cloudshell-user@ip-10-0-82-165 ~]$ aws rds describe-db-instances \
>   --query "*[].[DBInstanceIdentifier,Endpoint.Address,Endpoint.Port,MasterUsername]"
[
    [
        "database-1",
        "database-1.*****.us-east-1.rds.amazonaws.com",
        5432,
        "postgres"
    ]
]