执行sudo docker run -i -t ubuntu /bin/bash

出现下面的问题是什么原因？

Unable to find image 'ubuntu:latest' locally
latest: Pulling from library/ubuntu
c63fb41c2213: Pulling fs layer 
99fcaefe76ef: Pulling fs layer 
5a4526e952f0: Pulling fs layer 
1d073211c498: Pulling fs layer 
Pulling repository docker.io/library/ubuntu
Error while pulling image: Get https://index.docker.io/v1/repositories/library/ubuntu/images: net/http: TLS handshake timeout