docker pull 镜像发生如下错误，怎么解决啊？
➜ ~ docker version
Client:
Version: 17.04.0-ce
API version: 1.28
Go version: go1.7.5
Git commit: 4845c56
Built: Mon Apr 3 18:22:23 2017
OS/Arch: linux/arm
Server:
Version: 17.04.0-ce
API version: 1.28 (minimum version 1.12)
Go version: go1.7.5
Git commit: 4845c56
Built: Mon Apr 3 18:22:23 2017
OS/Arch: linux/arm
Experimental: false
最有可能是你的proxy有问题，检查你的proxy设置。