Thanks for providing your app id, but I’m not seeing the above error with the CreateCheckout call. In fact, I see several successful checkouts being created over the last few hours. Can you clarify when you’re seeing this, or perhaps you’re using a sandbox application id instead?
Update: I did find your sandbox application id calling it, not your production application. However, you’re using a production location_id, and not your sandbox location_id.
I was making calls to initialize the changes from my app itself, that would explain the calls you’re seeing.
I do like to use the API explorer first of course, so not sure how I overlooked using sandbox vs production location_id. Thanks again for all of your help with this and beyond.