CreatePayment endpoint of Square API

Are you adding the AskForShippingAddress method to your CreateCheckoutRequest.Builder?

var body = new CreateCheckoutRequest.Builder(idempotencyKey: null, order: null)
  .AskForShippingAddress(true)
  .Build();

I’ll admit I’m not terribly familiar with C#, but that is what we have generated for C# when adding true for that field in our API Explorer.