Because Android 4.1.2 is a legacy operating system, modern versions of the Play Store will not work on your device. You must install a specific, older version of the application.
Installing a Play Store APK on Android 4.1.2 is a . It will allow you to download and update legacy apps for a few more months or maybe a year. However, Google is gradually turning off backend API access for Android 4.1. play store apk android 412