its not related to theme. Its related to app, Please check the apps recently added by you. pause app one by one and test website. Hope this approach will help.
hey recently i have added one app to limit the quantity of a product to get added in cart, but then i uninstalled the app and now when i am trying to edit the checkout page it showing the same error and now i have no app installed
I don’t have that app installed. I removed the two apps I did have installed and it still didn’t work. I uninstalled Kalles and reinstalled it and it worked fine after that. So not associated with the app. Seems to have been a bad install of the theme.