使用sendmailR发送电子邮件时出错

Question

我想使用sendmailR通过smtp.exmail.qq.com服务器发送电子邮件，我查看了示例，但是失败了，我该如何解决？

sendmail(
      from="***@companyName.com",
      to="***@companyName.com",
      body="Hallo",   
      subject="from R procedure",
      control=list(smtpServer="smtp.exmail.qq.com"),
    )

Error in socketConnection(host = server, port = port, blocking = TRUE) : 
  cannot open the connection
In addition: Warning message:
In socketConnection(host = server, port = port, blocking = TRUE) :
  localhost:25 cannot be opened