@[TOC](突然出现了跨域问题connect() failed (111: Connection refused) while connecting to upstream)

前后端分离，前端突然报错，跨域，postman访问，提示查看Nginx的error.log…

nginx错误日志提示： 2020/09/03 16:24:38 [error] 6947#0: *15308 connect() failed (111: Connection refused) while connecting to upstream, 连接拒绝，telnet服务地址 检查对应端口的服务是否正常 结果，服务挂掉了，重启，ok了