ROS : unable to process source ; urlopen error timed out

jeremyma@jeremyma-virtual-machine:~$ sudo rosdep init
Wrote /etc/ros/rosdep/sources.list.d/20-default.list
Recommended: please run
rosdep update

jeremyma@jeremyma-virtual-machine:~$ rosdep update
reading in sources list data from /etc/ros/rosdep/sources.list.d
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml
Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
Skip end-of-life distro “ardent”
Skip end-of-life distro “bouncy”
Add distro “crystal”
Add distro “dashing”
Add distro “eloquent”
Skip end-of-life distro “groovy”
Skip end-of-life distro “hydro”
Skip end-of-life distro “indigo”
Skip end-of-life distro “jade”
Add distro “kinetic”
Skip end-of-life distro “lunar”
Add distro “melodic”
Add distro “noetic”
updated cache in /home/jeremyma/.ros/rosdep/sources.cache
ERROR: Not all sources were able to be updated.
[[[
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)
]]]
jeremyma@jeremyma-virtual-machine:~$ sudo apt-get update
命中:1 http://cn.archive.ubuntu.com/ubuntu xenial InRelease
命中:2 http://packages.ros.org/ros/ubuntu trusty InRelease
获取:3 http://security.ubuntu.com/ubuntu xenial-security InRelease [109 kB]
获取:4 http://cn.archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]
命中:5 https://mirrors.tuna.tsinghua.edu.cn/docker-ce/linux/ubuntu xenial InRelease
命中:6 https://packagecloud.io/github/git-lfs/ubuntu xenial InRelease
忽略:4 http://cn.archive.ubuntu.com/ubuntu xenial-updates InRelease
获取:7 http://cn.archive.ubuntu.com/ubuntu xenial-backports InRelease [107 kB]
获取:8 http://cn.archive.ubuntu.com/ubuntu xenial-updates Release [108 kB]
获取:9 http://cn.archive.ubuntu.com/ubuntu xenial-updates Release.gpg [916 B]
忽略:3 http://security.ubuntu.com/ubuntu xenial-security InRelease
获取:10 http://security.ubuntu.com/ubuntu xenial-security Release [108 kB]
获取:11 http://security.ubuntu.com/ubuntu xenial-security Release.gpg [916 B]
已下载 325 kB，耗时 2分 59秒 (1,811 B/s)
正在读取软件包列表… 完成
jeremyma@jeremyma-virtual-machine:~$ sudo rosdep init
ERROR: default sources list file already exists:
/etc/ros/rosdep/sources.list.d/20-default.list
Please delete if you wish to re-initialize
jeremyma@jeremyma-virtual-machine:~$ rosdep update
reading in sources list data from /etc/ros/rosdep/sources.list.d
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml
Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
Skip end-of-life distro “ardent”
Skip end-of-life distro “bouncy”
Add distro “crystal”
Add distro “dashing”
Add distro “eloquent”
Skip end-of-life distro “groovy”
Skip end-of-life distro “hydro”
Skip end-of-life distro “indigo”
Skip end-of-life distro “jade”
Add distro “kinetic”
Skip end-of-life distro “lunar”
Add distro “melodic”
Add distro “noetic”
updated cache in /home/jeremyma/.ros/rosdep/sources.cache

echo "source /opt/ros/indigo/setup.bash" >> ~/.bashrc  
source ~/.bashrc  

jeremyma@jeremyma-virtual-machine:~$ roscore
… logging to /home/jeremyma/.ros/log/c2150816-f245-11e9-966d-000c296d6763/roslaunch-jeremyma-virtual-machine-51987.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.
started roslaunch server http://jeremyma-virtual-machine:41693/
ros_comm version 1.11.16
**SUMMARY
========*
PARAMETERS

• /rosdistro: Debian
• /rosversion: 1.11.16
  NODES
  auto-starting new master
  process[master]: started with pid [52002]
  ROS_MASTER_URI=http://jeremyma-virtual-machine:11311/
  setting /run_id to c2150816-f245-11e9-966d-000c296d6763
  process[rosout-1]: started with pid [52015]
  started core service [/rosout]*