我尝试将mysql与golang连接，并报告了错误

My Test code likes:

package main
import (
        "fmt"
        "math/rand"
        "time"
        "log"
        "database/sql"
        _ "github.com/go-sql-driver/mysql"
)

func main() {

        db, err := sql.Open("mysql", "username:password@tcp(55b5f18rtr8895.sh.cdb.myqcloud.com:7863)/bsk")
        if err != nil {
                log.Println(err)
        }

        db.SetConnMaxLifetime(100 * 100)
        db.SetMaxIdleConns(10)
        db.SetMaxOpenConns(50)
        defer db.Close()

        db.Ping()
        err = db.Ping()
        if err != nil {
                log.Println(err)
        }

}

And the error is:

driver: bad connection

I am sure the mysql host and port is roght. But i just can't find any problems here, please help me.

I used db.Ping() twice, if one was removed than it works.