Those premium chests appear for a certain time (~30 minutes) and you only have this allotted time to open them for gems.
To open a chest, you need to click on it until the timer runs out and click on the "Open" button to get its rewards.
How to open the treasure chest with the timer that sometimes appears in my inn?
Last Updated: 611d
To open a chest, you need to click on it until the timer runs out and click on the "Open" button to get its rewards.