I have like a month with this issue. Every time I open the app, it pops up, then I press "ok" and it appears again and again and again. And every time I am working on a photo I can use the premium settings with no problem because I know I paid. It only happens when I'm on the gallery. Please help!
Is it possible you are signed into Lightroom using an account that is not your paid, subscribed Lightroom account? If you are indeed signed into the paid account, does it help to reinstall the app? (Be sure that Lightroom has completed syncing any recent photos or edits you've made, before you reinstall the app)