Hey @hasnainmalik - that is strange, from the screenshot you provided, it does look like you’ve formatted the scope properly in your env file. Can you try requesting the shopify_payments scope on the shop through your app and see if you’re able to make the API call that way? This scope is valid for the transactions API endpoint too. If this works - we would recommend continuing to use the shopify_payments scope, but I will do some more troubleshooting to see why the other scope is returning that OAuth error as well.
Hope to hear from you soon - if neither scope works, I’ll look into this further with my team, just let us know.
Al | Shopify Developer Support