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

The following mirrors should have the ISO images available:

http://mirror.dal.nexril.net/centos-altarch/7.7.1908/isos/i386/
http://ftp.osuosl.org/pub/centos-altarch/7.7.1908/isos/i386/
http://mirror.genesisadaptive.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.genesishosting.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.chpc.utah.edu/pub/centos-altarch/7.7.1908/isos/i386/
http://mirror.math.princeton.edu/pub/centos-altarch/7.7.1908/isos/i386/
http://mirror.atl.genesisadaptive.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.keystealth.org/centos-altarch/7.7.1908/isos/i386/
http://mirrors.xtom.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.lax.genesisadaptive.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.vcu.edu/pub/gnu_linux/centos-altarch/7.7.1908/isos/i386/
http://mirrors.ocf.berkeley.edu/centos-altarch/7.7.1908/isos/i386/
http://mirror.esecuredata.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.calgah.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.cedia.org.ec/centos-altarch/7.7.1908/isos/i386/
http://mirror.worria.com/centos-altarch/7.7.1908/isos/i386/
http://mirrors.xtom.nl/centos-altarch/7.7.1908/isos/i386/
http://mirror.usenet.farm/centos-altarch/7.7.1908/isos/i386/
http://mirrors.powernet.com.ru/centos-altarch/7.7.1908/isos/i386/
http://mirror.serverion.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.ufro.cl/centos-altarch/7.7.1908/isos/i386/
http://ftp.yz.yamagata-u.ac.jp/pub/linux/centos-altarch/7.7.1908/isos/i386/
http://mirror.nyherji.is/centos-altarch/7.7.1908/isos/i386/
http://centos.mirror.garr.it/centos-altarch/7.7.1908/isos/i386/
http://centos-altarch.mirror.liquidtelecom.com/7.7.1908/isos/i386/
http://mirrors.daticum.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.gadix.com/centos-altarch/7.7.1908/isos/i386/
http://mirrors.mivocloud.com/centos-altarch/7.7.1908/isos/i386/
http://mirror.xtom.com.hk/centos-altarch/7.7.1908/isos/i386/
http://mirrors.dotsrc.org/centos-altarch/7.7.1908/isos/i386/
+ others, see the full list of mirrors: https://www.centos.org/download/altarch-mirrors/

Mirrors verified Mon Apr 27 06:25:56 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