Install openpaas on CenOS 7 but no file founds

Hi , Please help
Im trying install openpaas on cent OS 7 using the following link
http://docs.open-paas.org/getting-started/linux/

after successful installing CenOS 7, i’ m running this installation guide:
yum erase -y postfix
yum install -y openpaas openpaas-davserver openpaas-james

but the message said. file is not found

Please Help, Thank you

BR,
ADTV

i ran into a ton of issues on redhat, you might want to use Ubuntu. If you get yum working on cent i have a whole bunch of fixes documented here