Hi @rizenindia,
Can you open the Customizer and navigate to “Appearance > Navigation > Layout” to check if the “Vertical Navigation Default State” field is on “open”, please ? If you don’t see the “Vertical Navigation Default State” field, it means you need to update your theme to the latest version first.
Also, please note that if a user opens or closes the navigation by manually clicking on the hamburger button, the status will be saved and the navbar will stay opened or closed, depending on their preference.
Best,