---
title: "W5500 MQTT 예제 오류 질문"
url: "https://maker.wiznet.io/forum/15110"
markdown_url: "https://maker.wiznet.io/forum/15110/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "sku4806"
created: "2024-01-05T03:45:56+09:00"
last_activity: "2024-01-05T07:59:50+09:00"
language: "ko"
views: 165
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 MQTT 예제 오류 질문

## Question

Asked by sku4806 on 2024-01-05 in Ethernet Chips.

![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/5/585a1f39835457be2087a6db508410b5401b1f11.png)

mqtt process loop error :4 라고 되어 있는데 어떻게 해결 해야 하나요?

## Replies

### Reply 1 by Eugeny, 2024-01-05

search for `mqtt_transport_yield` gives no results. You must look into the source you have to identify the cause of the error. MQTT 3.1.1 defines connect error 4 as “Connection rejected for damaged username or password - The data in the username or password is in the wrong format”, or it may just happen that connection was dropped.

---

Source: https://maker.wiznet.io/forum/15110