add

src/Api/Billing/Controllers/StripeController.cs

@@ -74,6 +74,8 @@ public class StripeController(
                 },
             }
         };
+        try
+        {
             var taxCalculation = await stripeAdapter.CalculateTaxAsync(options);
             var response = new CalculateTaxResponseModel
             {
@@ -86,4 +88,9 @@ public class StripeController(
             };
             return TypedResults.Ok(response);
         }
+        catch (StripeException e)
+        {
+            return TypedResults.BadRequest(e.Message);
+        }
+    }
 }