Before passing from the "Design" tab to the "Share settings' tab, you need to make sure you don't have any "errors" on your page.
1. Check for a red error signal on the top right corner of the interface. If there is one, click on it.
💡 You won't be able to publish or update your Smartpage if you don't solve all the errors first.
2. Click on the error you want to fix in the drop-down menu. It will open the edit menu for the corresponding block.
3. Fix the error in the Block's editing menu.
4. Well done Switcher! 🧙♂️ You have successfully corrected an error! 🎉