Error calling cancel order api in public app

but giving this error:
This action requires merchant approval for write_orders scope
my app is public app not private.pls help me.

The OAuth process where the Shopify user accepts the prompted access permissions should have this option included. Your app that you have created should include this, so that when the user completes the OAuth process they have granted access to all of the proper scopes.

SHOPIFY_API_SCOPE = os.environ.get(‘SHOPIFY_API_SCOPE’, ‘read_products,write_products,read_orders,write_orders’).split(‘,’)

yes before installation i changed permission as above write_orders.