It is obvious most people can't download any app from G.play store, i know you must have seen lot of solution like clearing the cache, clearing phone data, but what most people dont understand abt andriod is that, all the default app on andriod sometimes get faulty and their is alway an alternative app including the installer, you can alway find an alternative installer,
The problem of not been able to download from g.play store is the Phone default DOWNLOAD MANAGER,, all you have to do is to search download manager in mogenie or google. After download , install then goto G.playstore,
NB: Try it twice, if you still got error