无法通过Golang连接到Postgres数据库

Question

I am using Golang to connect to a Postgres DB instance.

When the code below is executed from an Amazon EC2 instance, the error is not nil after sql.open().

db, err := sql.Open("postgres", "postgres://username:[e-mail]/postgres?sslmode=disable")

    if err != nil {
        check(err)
        panic(err)
    }

    err = db.Ping()

    if err != nil {
        check(err)
        panic(err)
    }

However, when I run db.Ping() it doesn't do anything. The code after db.ping() doesn't seem to be executed. After a while I get getsockopt: connection timed out in the terminal window.

What could be the problem? Also even when I use the wrong password, the error is still not nil.