Insufficient Space on Mobile Device
This problem may occur when your memory cache is insufficient.

When you download an app, the data goes in the cache so that the phone can install it when the download is completed.



In order to be sure that this is the problem, try to download smaller apps. There must be a point where the size is small enough for your android to install it.

I had this problem on my Acer Stream years ago and this is what the support told me, which was right. What is your smartphone model ?