update

ts/bunq.classes.account.ts

@@ -114,13 +114,22 @@ export class BunqAccount {
       throw new Error('Creating sandbox users only works in sandbox environment');
     }
 
-    const response = await this.apiContext.getHttpClient().post(
-      '/v1/sandbox-user-person',
-      {}
+    // Sandbox user creation doesn't require authentication
+    const response = await plugins.smartrequest.request(
+      'https://public-api.sandbox.bunq.com/v1/sandbox-user-person',
+      {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'User-Agent': 'bunq-api-client/1.0.0',
+          'Cache-Control': 'no-cache'
+        },
+        requestBody: '{}'
+      }
     );
 
-    if (response.Response && response.Response[0] && response.Response[0].ApiKey) {
-      return response.Response[0].ApiKey.api_key;
+    if (response.body.Response && response.body.Response[0] && response.body.Response[0].ApiKey) {
+      return response.body.Response[0].ApiKey.api_key;
     }
 
     throw new Error('Failed to create sandbox user');