There are something wrong with github because main repo exist in github.
Try modified /etc/yum.repos.d/mratwork.repo where:
#mirrorlist=http://rpms.mratwork.com/repo/mirrors/
change to:
mirrorlist=http://rpms.mratwork.com/repo/mirrors/
and then 'yum clean all'.
If still not work, change:
https://github.com/mustafaramadhan/kloxo/raw/rpms
to:
http://rpms.mratwork.com/repo/mratwork/
and then 'yum clean all'.