apt-get update 中出现这个错误是什么：无法连接
我的互联网连接正常且速度很快（没有代理网络），但当我尝试apt-get 更新：
~ $ Sudo apt-get update
[Sudo] password for amaponian:
Des: 1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Err: 2 http://ve.archive.ubuntu.com/ubuntu xenial InRelease
Unable to start the connection to ve.archive.ubuntu.com:80 (2801: 82: 80ff: 8000 :: 5). - connect (101: The network is inaccessible) [IP: 2801: 82: 80ff: 8000 :: 5 80]
Err: 3 http://ve.archive.ubuntu.com/ubuntu xenial-updates InRelease
Unable to start the connection to ve.archive.ubuntu.com:80 (2801: 82: 80ff: 8000 :: 5). - connect (101: The network is inaccessible) [IP: 2801: 82: 80ff: 8000 :: 5 80]
Err: 4 http://ve.archive.ubuntu.com/ubuntu xenial-backports InRelease
Unable to start the connection to ve.archive.ubuntu.com:80 (2801: 82: 80ff: 8000 :: 5). - connect (101: The network is inaccessible) [IP: 2801: 82: 80ff: 8000 :: 5 80]
0% [1 InRelease 1.140 B / 102 kB 1%]