Subscription not working on my other android device
I've just purchased the 1-month fixed term subscription from Google Play on my phone and it works from my phone. However, when I start the app on my other android tablet, it tells me "upgrade to full protection". When I then go to the subscription page and tap on the 1-month fixed term subscription, I get the message "Error. You already own this item." All my android devices use the same Google account.
Can someone help?