问正在尝试创建电子邮件脚本，但并非所有收件人都收到该电子邮件

EN

import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from email.mime.base import MIMEBase
from email import encoders

email_user = 'myemail@gmail.com'
email_send = 'otheremail1@gmail.com, otheremail2@gmail.com'
subject = 'Test'

msg = MIMEMultipart()
msg['From'] = email_user
msg['To'] = email_send
msg['Subject'] = subject

body = """Hello,

This is a test.

Thanks!"""
msg.attach(MIMEText(body,'plain'))

filename='dataset.csv'
attachment =open(filename,'rb')

part = MIMEBase('application','octet-stream')
part.set_payload((attachment).read())
encoders.encode_base64(part)
part.add_header('Content-Disposition',"attachment; filename= "+filename)

msg.attach(part)
text = msg.as_string()
server = smtplib.SMTP('smtp.office365.com',587)
server.starttls()
server.login(email_user,'password')

server.sendmail(email_user,email_send,text)
server.quit()