Cloud Run: <Cloud SQL instance IP address>: 3306: connect: connect timed out

I want to connect Cloud SQL in Cloud Run Application. I have used golang. Here is the code around the SQL connection setup.

func getEnv(key, def string) string {
    v := os.Getenv(key)
    if v == "" {
        return def
    }
    return v
}

        DB: DB{
            User:     getEnv("DB_USER", "<user name>"),
            Pass:     getEnv("DB_PASS", "<password>"),
            Host:     getEnv("DB_HOST", "0.0.0.0"),
            Port:     getEnv("DB_PORT", "3306"),
            Database: getEnv("DB_DATABASE", "<database name>"),
        },

    dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8&parseTime=true",
        config.DB.User, config.DB.Pass, config.DB.Host, config.DB.Port, config.DB.Database)

    db, err := gorm.Open("mysql", dsn)

I have environment variables set on the Cloud Run settings console. After delpoy the app, the Cloud Run console shows up Cloud Run error: Container failed to start. Failed to start and then listen on the port defined by the PORT environment variable. Logs for this revision might contain more information.and dial tcp <Cloud SQL Private IP> :3306: connect: connection timed outI wonder if the SQL connection is wrong...