ftp连不上一般是什么原因（ECS)

响应:         220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------

响应:         220-You are user number 2 of 50 allowed.

响应:         220-Local time is now 21:22. Server port: 21.

响应:         220-This is a private system - No anonymous login

响应:         220-IPv6 connections are also welcome on this server.

响应:         220 You will be disconnected after 15 minutes of inactivity.

命令:         AUTH TLS

错误:         20 秒后无活动，连接超时

错误:         无法连接到服务器