CentOS - Jun 2017 - what is causing this problem ... (yum, fastest mirror)

Hello,

what is causing the following, and can someone give the solution which is
mentioned at https://access.redhat.com/articles/1320623

by the way: why are the "fastest" mirrors from other continent?

[root at host sysconfig]# yum clean all
Loaded plugins: fastestmirror, security
Cleaning repos: base epel extras updates
Cleaning up Everything
Cleaning up list of fastest mirrors

[root at host sysconfig]# yum clean all
Loaded plugins: fastestmirror, security
Cleaning repos: base epel extras updates
Cleaning up Everything

[root at host sysconfig]# yum update
Loaded plugins: fastestmirror, security
Setting up Update Process
Determining fastest mirrors
epel/metalink | 12 kB 00:00
* base: mirror.genesisadaptive.com
* epel: mirror.us.leaseweb.net
* extras: mirror.genesisadaptive.com
* updates: mirror.genesisadaptive.com
base | 3.7 kB 00:00
base/primary_db | 4.7 MB 00:01
epel | 4.3 kB 00:00
http://mirror.us.leaseweb.net/epel/6/x86_64/repodata/repomd.xml: [Errno
-1] repomd.xml does not match metalink for epel
Trying other mirror.
epel | 4.3 kB 00:00
https://download-ib01.fedoraproject.org/pub/epel/6/x86_64/repodata/repomd.xml:
[Errno -1] repomd.xml does not match metalink for epel
Trying other mirror.
epel | 4.2 kB 00:00
https://mirror.us-midwest-1.nexcess.net/epel/6/x86_64/repodata/c259ce09172fc535ff3b556ccad8d2a02f128a2da95f0c1389ce9443800e225d-primary.sqlite.bz2:
[Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not
Found"
Trying other mirror.
To address this issue please refer to the below knowledge base article
https://access.redhat.com/articles/1320623
If above article doesn't help to resolve this issue please open a ticket
with Red Hat Support.
http://ftp.linux.ncsu.edu/pub/epel/6/x86_64/repodata/c259ce09172fc535ff3b556ccad8d2a02f128a2da95f0c1389ce9443800e225d-primary.sqlite.bz2:
[Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not
Found"
Trying other mirror.
epel/primary_db | 5.9 MB 00:01
extras | 3.4 kB 00:00
extras/primary_db | 29 kB 00:00
updates | 3.4 kB 00:00
updates/primary_db | 2.0 MB 00:01
No Packages marked for Update