Fix Minecraft 'io.netty.channel.AbstractChannel' Connection Refused

Updated: 11/29/2025

You copy the server IP, hit join, and wait. The screen hangs on 'Connecting...' before slapping you with a massive wall of text: io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information. While this looks like complicated java code, it is actually very simple: Your computer found the server, but your Firewall slammed the door in its face.

Table of Contents

What does 'Connection Refused' mean?

Minecraft runs on Java. When you try to connect to a server (especially a local LAN server or a modded server), your PC sends a request via a specific port (usually 25565). If Windows Firewall or your Router thinks this request is dangerous, it terminates the connection instantly, resulting in the 'Netty' error.

Method 1: Allow Java Through Windows Firewall

This is the #1 cause. If Java updated recently, your Firewall rules might still be pointing to the old version.

Step 1: Open Firewall Settings

Press the Windows Key and type 'Allow an app through Windows Firewall'. Click the top result.

Step 2: Change Settings

Click the button that says Change Settings (Admin rights required). Scroll down until you see Java(TM) Platform SE Binary.

Step 3: Check Both Boxes

You will likely see multiple 'Java' entries. You must ensure that BOTH the 'Private' and 'Public' checkboxes are ticked for every single Java entry. If they are unchecked, the connection is blocked on public networks.

Method 2: Reset Your IP Configuration

If your IP address changed (dynamic IP) but the router still thinks you are on the old one, packets get lost.

Note: This will disconnect your internet for about 5 seconds.

Step 1: Open Command Prompt

Run CMD as Administrator.

Step 2: Release and Renew

Type these commands in order:

ipconfig /release ipconfig /flushdns ipconfig /renew

Once you see your new IP address appear, try joining the server again.

Method 3: Check Port Forwarding (For Server Hosts)

If you are the one hosting the server and your friends get this error, you probably didn't forward the port correctly.

  • Log into your Router Admin page (usually 192.168.1.1).
  • Find Port Forwarding.
  • Ensure Port 25565 (TCP/UDP) is forwarded to your computer's IPv4 address.