不同的服务器具有不同的安全要求.如果要处理所有这些问题，则在应用程序中将需要一些特殊情况.

Different servers have different security requirements. If you want to handle all of them, you're going to need some special cases in your application.

有时候，您需要用户为电子邮件服务器创建应用专用密码.

Sometimes you'll need the user to create an app-specific password for the email server.

有时候，如果服务器支持，则需要支持 OAuth .

Sometimes you'll need to support OAuth if the server supports it.