# Facing error ‘Server closed connection without DISCONNECT’ when HiveMQ client tries to connect to EMQX broker

**URL:** <https://community.hivemq.com/t/facing-error-server-closed-connection-without-disconnect-when-hivemq-client-tries-to-connect-to-emqx-broker/1872>\
**Category:** HiveMQ Community Edition\
**Created:** [March 7, 2023, 7:53am UTC](https://community.hivemq.com/t/facing-error-server-closed-connection-without-disconnect-when-hivemq-client-tries-to-connect-to-emqx-broker/1872 "2023-03-07T07:53:56Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![hivemqclient](https://avatars.discourse-cdn.com/v4/letter/h/5e9695/32.png) [@hivemqclient](https://community.hivemq.com/u/hivemqclient)\
**Post date:** [March 7, 2023, 7:53am UTC](https://community.hivemq.com/t/facing-error-server-closed-connection-without-disconnect-when-hivemq-client-tries-to-connect-to-emqx-broker/1872/1 "2023-03-07T07:53:56Z")

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Hi everyone,

Am using an android based client to publish to EMQX broker. Details on both:  
Android Client: HiveMQ v1.3.0  
Broker: EMQX v5.0.9 (3 core nodes, 0 replica nodes)

Upon scaling to almost 3000 connections, I started facing the following issue: com.hivemq.client.mqtt.exceptions.ConnectionClosedException: Server closed connection without DISCONNECT. Is this an issue specific to HiveMQ client or a scaling issue with EMQX ?

Would be great if someone can help here. Thanks in advance.

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**Author:** ![sauroter](https://yyz1.discourse-cdn.com/flex035/user_avatar/community.hivemq.com/sauroter/32/18_2.png) [@sauroter](https://community.hivemq.com/u/sauroter)\
**Post date:** [March 7, 2023, 8:05pm UTC](https://community.hivemq.com/t/facing-error-server-closed-connection-without-disconnect-when-hivemq-client-tries-to-connect-to-emqx-broker/1872/2 "2023-03-07T20:05:29Z")

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Hello,

Unfortunately, we are unable to provide you with any specific information regarding your Broker as we have no knowledge of the products offered by EMQ.

We utilized the HiveMQ MQTT Client as the foundation for our HiveMQ Swarm product. Recently, we published a [white paper](https://www.hivemq.com/whitepaper/achieving-200-mil-concurrent-connections-with-hivemq/) demonstrating the scalability of the HiveMQ Platform, using HiveMQ Swarm and the HiveMQ MQTT Client to achieve a benchmark of 200 million connections.

Furthermore, the log message you provided,

> “com.hivemq.client.mqtt.exceptions.ConnectionClosedException: Server closed connection without DISCONNECT,”

strongly suggests an action taken by the server, although we cannot guarantee this due to our lack of knowledge about EMQ.

Best regards,  
Georg

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**Author:** ![ThanHtayAung](https://avatars.discourse-cdn.com/v4/letter/t/e480ec/32.png) [@ThanHtayAung](https://community.hivemq.com/u/ThanHtayAung)\
**Post date:** [August 31, 2025, 8:47pm UTC](https://community.hivemq.com/t/facing-error-server-closed-connection-without-disconnect-when-hivemq-client-tries-to-connect-to-emqx-broker/1872/3 "2025-08-31T20:47:15Z")

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Hello Sir,

How many device can hivemq opensource connect.

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**Author:** ![hivemq-support](https://yyz1.discourse-cdn.com/flex035/user_avatar/community.hivemq.com/hivemq-support/32/357_2.png) [@hivemq-support](https://community.hivemq.com/u/hivemq-support)\
**Post date:** [October 9, 2025, 9:15am UTC](https://community.hivemq.com/t/facing-error-server-closed-connection-without-disconnect-when-hivemq-client-tries-to-connect-to-emqx-broker/1872/4 "2025-10-09T09:15:10Z")

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Hello @ThanHtayAung

Welcome to HiveMQ Community Forum.

HiveMQ community edition (Open Source) can support **tens of thousands of clients** on a single broker, depending on your hardware and workload.

1. There is no hard-coded cap, but you are limited by your machine resources.
2. For very large IoT deployments (100k+ devices), [HiveMQ Enterprise](https://docs.hivemq.com/hivemq/latest/user-guide/getting-started.html) with clustering is the recommended path as it supports **clustering, scaling, and advanced monitoring**.

Regards,  
Sheetal from HiveMQ team