In order to conserve the limited bandwidth available, ISO images are not downloadable from mirror.centos.org

http://mirror.centos.iad1.serverforge.org/8.1.1911/isos/aarch64/
http://mirrors.advancedhosters.com/centos/8.1.1911/isos/aarch64/
http://mirror.vtti.vt.edu/centos/8.1.1911/isos/aarch64/
http://us.mirror.nsec.pt/centos/8.1.1911/isos/aarch64/
http://mirror.vcu.edu/pub/gnu_linux/centos/8.1.1911/isos/aarch64/
http://mirror.cs.vt.edu/pub/CentOS/8.1.1911/isos/aarch64/
http://centos4.zswap.net/8.1.1911/isos/aarch64/
http://mirror.ash.fastserv.com/centos/8.1.1911/isos/aarch64/
http://mirror.cogentco.com/pub/linux/centos/8.1.1911/isos/aarch64/
http://repo1.ash.innoscale.net/centos/8.1.1911/isos/aarch64/
http://repos-va.psychz.net/centos/8.1.1911/isos/aarch64/

http://mirror.jaleco.com/centos/8.1.1911/isos/aarch64/
http://repo1.sea.innoscale.net/centos/8.1.1911/isos/aarch64/
http://mirror.mojohost.com/centos/8.1.1911/isos/aarch64/
http://repos.mia.quadranet.com/centos/8.1.1911/isos/aarch64/
http://mirrors.lug.mtu.edu/centos/8.1.1911/isos/aarch64/
http://mirror.fileplanet.com/centos/8.1.1911/isos/aarch64/
http://mirror.netdepot.com/centos/8.1.1911/isos/aarch64/
http://repos.dfw.quadranet.com/centos/8.1.1911/isos/aarch64/
http://ftp.osuosl.org/pub/centos/8.1.1911/isos/aarch64/
http://mirror.linux.duke.edu/pub/centos/8.1.1911/isos/aarch64/
http://mirrors.seas.harvard.edu/centos/8.1.1911/isos/aarch64/
http://ewr.edge.kernel.org/centos/8.1.1911/isos/aarch64/
http://centos-distro.1gservers.com/8.1.1911/isos/aarch64/
http://reflector.westga.edu/repos/CentOS/8.1.1911/isos/aarch64/
http://repo1.dal.innoscale.net/centos/8.1.1911/isos/aarch64/
http://bay.uchicago.edu/centos/8.1.1911/isos/aarch64/
http://mirror.den01.meanservers.net/centos/8.1.1911/isos/aarch64/
http://mirror.genesishosting.com/centos/8.1.1911/isos/aarch64/
http://centos.mirror.lstn.net/8.1.1911/isos/aarch64/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/

Mirrors verified Thu Jun 4 05:30:29 2020 UTC

You can also download the ISO images using bittorrent, a peer-to-peer file sharing protocol. The .torrent files can be found from CentOS mirrors. Various bittorrent clients are available, including (in no particular order of preference): utorrent, vuze (Azureus), BitTorrent, Deluge, ctorrent, ktorrent, rtorrent and transmission. Packaged copies of various torrent clients for CentOS can be found in the repositories listed in the following wiki article: https://wiki.centos.org/AdditionalResources/Repositories