yum error 2

Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist
http://mirrorlist.fedora.org/?release=20&arch=x86_64&repo=os error was
14: PYCURL ERROR 7 - "Failed to connect to
2a02:2498:1:3d:5054:ff:fed3:e91a: Network is unreachable"
Error: Cannot find a valid baseurl for repo: base

http://mirror.nexcess.net/fedora/20/x86_64/repodata/repomd.xml:

[Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.

http://mirrordenver.fdcservers.net/fedora/20/x86_64/repodata/repomd.xml:

[Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.

http://mirrors.cmich.edu/fedora/20/x86_64/repodata/repomd.xml:

[Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.