vscode搭建flutter环境在执行完flutterpackagesget就出现了错误?

1.获取包获取不到

2.已经设置了国内镜像

3.`Running "flutter packages get" in myapp...
Got socket error trying to find package cupertino_icons at https://pub.flutter-io.cn.

pub get failed (69) -- attempting retry 1 in 1 second...`
4.这种问题怎么解决,搜了一圈也没有个解决办法