In order to conserve the limited bandwidth available, ISO images are not downloadable from mirror.centos.org
The following mirrors in your region should have the ISO images available:
http://mirrors.cqu.edu.cn/CentOS/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirror.lzu.edu.cn/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.neusoft.edu.cn/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.zju.edu.cn/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.tuna.tsinghua.edu.cn/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.163.com/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.huaweicloud.com/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.aliyun.com/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://ftp.sjtu.edu.cn/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirror.jdcloud.com/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.njupt.edu.cn/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirror.bit.edu.cn/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirrors.cn99.com/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
Other mirrors further away:
http://ftp.yzu.edu.tw/Linux/CentOS/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://centos.cs.nctu.edu.tw/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://ftp.stu.edu.tw/Linux/CentOS/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://ftp.tc.edu.tw/Linux/CentOS/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://free.nchc.org.tw/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://ftp.twaren.net/Linux/CentOS/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirror01.idc.hinet.net/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://ftp.ksu.edu.tw/pub/CentOS/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://ftp.isu.edu.tw/pub/Linux/CentOS/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirror-hk.koddos.net/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://ftp.cuhk.edu.hk/pub/Linux/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://repo.virtualhosting.hk/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://centos.communilink.net/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirror.vpshosting.com.hk/pub/linux/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://repos.cianhost.net/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://centos.01link.hk/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
http://mirror.xtom.com.hk/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/
Mirrors verified Thu Aug 15 06:02:02 2019 UTC
