[cybmole]

On a non amazon tablet, the apps bought from amazon rely on the amazon store app to "phone home" for them and check licences. so e.g. your apps bought from amazon will stop working if you remove the amazon store app, or if you are offline for a long time ( not sure how long).

As you are using a Kindle fire, it's simpler, you normally just need to have wifi active for when the device decides to check licences - that.s normally when the app is launched, but not all apps require a check for every launch.

if you drag down from top of KF screen to access settings, you then have a sync option - tap that to force a sync of "everything" , with wifi active, and you shoudl be good to go.