I noticed that some peoples are having issues with downloading games that purchased in Spring Sale. Same happenned with me
so i found a solution that works for me, hope it works for you too
SOLVED !
logout your battlenet and right on top the login screen click on the engine change the region to Europe. that might resolve (worked for me)
Sorry bad english.
6 Likes
bro, you a lifesaver
bro ur amazing thank u
thank you this solved my problem as well ! 
couldnt install w3 battle chest before and now i can .
working thanks bro 
this was just stupid from the app and programmers 