Shared Preferences get lost after shutting down device or killing the app

Hi,

I am using Shared Preferences for storing and retrieving values like UserName and One token.

Here I am saving the UserName and token into Shared Preferences while user signing in. and also I can get the data from Shared Preferences after signing in.

But Shared Preferences get lost after shutting down device or killing the app.

Really am frustrated of it, Please anyone reply for my question.

Thanks