Hi @Aneo-1-1, thank you for subscribing to Windy Premium!

In which step does it fail? Is there any error message?

Have you tried to follow the instruction? https://community.windy.com/topic/11832/what-to-do-if-you-can-t-access-your-windy-premium-features
Note that you have to restore the purchase on device you originally subscribed to Windy Premium. If it was on your phone but not through App Store or Google Play, you have to do it in the browser (you paid via FastSpring). If you subscribed via FastSpring, restoring the purchase won't work in the app.