I've been staring at a prohibitory screen of my friends Imac while I try to boot it from a External hard drive that I created with createinstallmedia. Unable to

I've been staring at a prohibitory screen of my friends Imac while I try to boot it from a External hard drive that I created with createinstallmedia. Unable to install from store because “This item is temporarily unavailable, try again later” ACMT and I really don't want anyone to bring me the systems anymore. It really is soul crushing sometimes dealing with this software. Gone are the days where "It just works" And I worked for Applecare back when they had powerbooks and logic board issues.