Can't install CoursePress


I can't install CoursePress, sometimes it gives error 404 (or something like that saying it was not found), now it gives the error attached, I tried installing from the website as well and it gives me the same error..

I reseted my website and I'm doing everything from scratch, but before the reset I had the same problem trying to install it, then out of a sudden I was able to install.. after trying and trying.. what's going on?