Cannot download apps on Play Store without WiFi

Hi,

If I browse the Play Store, using my mobile data network, then the Play Store always asks me if I want to download the app over WiFi because it is a very large app. Whether I tick or untick the box to use WiFi for the download, doesn't matter, the result stays the same : my phone waits for a WiFi connection.

My phone does this for almost every app. It only allows me to download apps under 1MB or something to be downloaded using the mobile data network.
How can I increase this limit?...

Cannot download apps on Play Store without WiFi