Please ensure that there's no caching proxy between you and the repo (this is a quite common issue). 
It works fine on my box.

I've rebuilt the repo. Let me know if that helps.

Just add 

LOCAL_INTERFACES = <; 0.0.0.0:255 ; 0.0.0.0:4655

and so on to mail's custom MTA configuration;

I'm not sure how did you get 0777, but the only operations in Ajenti that change website root permissions (not even /var/www!) are Create root / Fix permissions (chowns to www-data) and Automatic downloader (chmods to 755/644).

Bitte schön :)

In case you were using EL7, I just found out that EPEL developers have changed the EPEL package URL. I've updated the EL7 quick-install script to reflect this change, so that now you can try running it again.