Assistant API calling in Flutter [SOLVED]

Hello, I’m trying to use Assistant API in Flutter.
Below me is the code for the Chatcompletion I want. I first had a message interruption because of the time was the short. That’s why I tried to change connectionTimeOut to a minute. But I still get an error that it wont work. Visible under the code.

import 'package:chat_gpt_sdk/chat_gpt_sdk.dart';

Future<void> getChatCompletion() async {
    const String token = 'API-KEY';
    final openAI =
        token: token,
        baseOption: HttpSetup(
          receiveTimeout: const Duration(seconds: 5),
          connectTimeout: const Duration(seconds: 60)),
        enableLog: true);
    const String assistantId = "ASSISTANT-ID";

    final request = CreateThreadAndRun(assistantId: assistantId, thread: {
      "messages": [
        {"role": "user", "content": "$_linesText"}

    // Create the thread and run
    final response =
        await openAI.threads.runs.createThreadAndRun(request: request);

    // Extract threadId from the response
    final threadId = response.threadId;

    // Retrieve messages
    final mMessage = await openAI.threads.messages.retrieveMessage(
      threadId: threadId,
      messageId: '',

    print("Response: ${mMessage.content[0].text?.value}");
[OpenAI] starting request
[OpenAI] request body :{assistant_id: asst_k66DjzXXXXXXXmqJTbe3, thread: {messages: [{role: user, content: [VUILZAK GROEN 50L, 20 MARLBORO RED, 20 MARLBORO RED, B.MASSARD BRUT, SUPER PAPRIKA LAYS, 4X20CLFEVERTREEMED, 10M DDL BAKPAPIER, 10C MANO PUISS BIO, 180G TONY CHOCOLAD, 6X1.5L COKE ZER0]}]}}
E/flutter (22020): [ERROR:flutter/runtime/] Unhandled Exception: status code :500  message :{message: null, code: null, type: null}
E/flutter (22020): 
E/flutter (22020): #0 (package:chat_gpt_sdk/src/client/openai_client.dart:229:7)
E/flutter (22020): <asynchronous suspension>
E/flutter (22020): #1      _ScannerState.getChatCompletion (package:smartberging/pages/Scanner.dart:334:9)
E/flutter (22020): <asynchronous suspension>
E/flutter (22020): 
[OpenAI] error code: null, message :The connection errored: Failed host lookup: '' This indicates an error which most likely cannot be solved by the library. data:null