Unable to restore purchase – Gas Cubby by Fuelly - MPG, Mileage & Fuel Economy Review

I have a subscription through Aug 2021, but can’t restore the purchase through the app. The iTunes password field that appears doesn’t show the keyboard and I can’t paste a password either. I keep getting notified to Upgrade to Premium, but have an active subscription. What to do?
Review by mujalifah on Gas Cubby by Fuelly - MPG, Mileage & Fuel Economy.