Quit working after telling me to buy the app

I’ve been using it with few issues for several months but today it randomly popped up a message telling me to purchase the app. It then closed and now won’t re-launch. I had already bought the app, and I tried uninstalling and reinstalling from the App Store but it still doesn’t work.

I don’t know how the app tries to detect a pirated version… but it isn’t working apparently.

estmatic about Grids for Instagram