通过jordan-wright / email.v1发送的Golang电子邮件

I'm writing web server and I need to send email message through my server. I tried to do as it's written in examples, but I get error:
EXTRA x509.UnknownAuthorityError=x509: certificate signed by unknown authority
My code is below:

inviteEmail := email.NewEmail() //it was said that email.v1 imported as email
inviteEmail.From = MyEmail
inviteEmail.To = make([]string, 1)
inviteEmail.To[0] = emailstr //is reciever's email
inviteEmail.Subject = "Test"
inviteEmail.Text = []byte("Welcome " + emailstr + " 
Your link is localhost:8080")
err = inviteEmail.Send("smtp.gmail.com:587", smtp.PlainAuth("", MyGmail, MyGmailPassword, "smtp.gmail.com"))
if err != nil {
    logger.Error("ERROR : ", err)
} else {
    logger.Info("Email sent")
}

upd: I tried to use both MyGmail and MyGmailLogin (without @gmail.com) in PalinAuth but I always get error.

Has anybody faced it? Maybe problem is because server is on localhost?