Failed to start 1.21.1 NeoForge server

[Onseshigo]

Describe the problem

I have tried both java25 and latest versions and tried repulling the image.

Container definition

services:
  mc-aero:
    image: itzg/minecraft-server:java25
    pull_policy: daily
    tty: true
    stdin_open: true
    network_mode: host
    ports:
      - "25565:25565"
    environment:
      EULA: "TRUE"
      MEMORY: "8G"
      TYPE: NEOFORGE
      DIFFICULTY: hard
      ALLOW_FLIGHT: true
      MAX_TICK_TIME: 300000
      NEOFORGE_INSTALLER: "/data/neoforge-21.1.227-installer.jar"
    volumes:
      - ./data:/data
      - ./downloads:/downloads
      - ./mods:/mods

Container logs

mc-aero-1  | [init] Running as uid=1000 gid=1000 with /data as 'drwxr-xr-x 2 1000 1000 4096 Apr 20 15:04 /data'
mc-aero-1  | [init] Image info: buildtime=2026-04-16T18:42:06.136Z,version=java25,revision=97407c672fccc431e5eca6d4c1d008972b5f230f
mc-aero-1  | [init] Resolving type given NEOFORGE
mc-aero-1  | [mc-image-helper] 15:18:19.732 ERROR : 'install-neoforge' command failed. Version is 1.56.3
mc-aero-1  | me.itzg.helpers.errors.GenericException: Unexpected format of id from Forge installer's version.json: neoforge-21.1.227
mc-aero-1  |    at me.itzg.helpers.forge.ProvidedInstallerResolver.extractFromVersionJson(ProvidedInstallerResolver.java:133)
mc-aero-1  |    at me.itzg.helpers.files.IoStreams.readFileFromZip(IoStreams.java:29)
mc-aero-1  |    at me.itzg.helpers.forge.ProvidedInstallerResolver.extractVersion(ProvidedInstallerResolver.java:61)
mc-aero-1  |    at me.itzg.helpers.forge.ProvidedInstallerResolver.resolve(ProvidedInstallerResolver.java:33)
mc-aero-1  |    at me.itzg.helpers.forge.ForgeLikeInstaller.install(ForgeLikeInstaller.java:54)
mc-aero-1  |    at me.itzg.helpers.forge.InstallNeoForgeCommand.call(InstallNeoForgeCommand.java:96)
mc-aero-1  |    at me.itzg.helpers.forge.InstallNeoForgeCommand.call(InstallNeoForgeCommand.java:20)
mc-aero-1  |    at picocli.CommandLine.executeUserObject(CommandLine.java:2031)
mc-aero-1  |    at picocli.CommandLine.access$1500(CommandLine.java:148)
mc-aero-1  |    at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2469)
mc-aero-1  |    at picocli.CommandLine$RunLast.handle(CommandLine.java:2461)
mc-aero-1  |    at picocli.CommandLine$RunLast.handle(CommandLine.java:2423)
mc-aero-1  |    at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:2277)
mc-aero-1  |    at picocli.CommandLine$RunLast.execute(CommandLine.java:2425)
mc-aero-1  |    at picocli.CommandLine.execute(CommandLine.java:2174)
mc-aero-1  |    at me.itzg.helpers.McImageHelper.main(McImageHelper.java:178)
mc-aero-1  | [init] [ERROR] Failed to installForge given installer /data/neoforge-21.1.227-installer.jar
mc-aero-1 exited with code 1

[itzg]

Can you try regular automation instead of forcing your own installer?

I'll look into the issue at some point.

[Onseshigo]

mc-aero-1  | ++ mc-image-helper java-release
mc-aero-1  | + ((  25 >= 17  ))
mc-aero-1  | + MC_IMAGE_HELPER_OPTS+=' --enable-native-access=ALL-UNNAMED'
mc-aero-1  | + export MC_IMAGE_HELPER_OPTS
mc-aero-1  | + export HOME=/data
mc-aero-1  | + HOME=/data
mc-aero-1  | ++ id -u
mc-aero-1  | ++ id -g
mc-aero-1  | ++ ls -lnd /data
mc-aero-1  | + log 'Running as uid=1000 gid=1000 with /data as '\''drwxr-xr-x 2 1000 1000 4096 Apr 20 15:04 /data'\'''
mc-aero-1  | + local oldState
mc-aero-1  | ++ shopt -po xtrace
mc-aero-1  | + oldState='set -o xtrace'
mc-aero-1  | + shopt -u -o xtrace
mc-aero-1  | [init] 2026-04-20 15:44:40+00:00 Running as uid=1000 gid=1000 with /data as 'drwxr-xr-x 2 1000 1000 4096 Apr 20 15:04 /data'
mc-aero-1  | ++ paste -d, -s /etc/image.properties
mc-aero-1  | + log 'Image info: buildtime=2026-04-16T18:42:06.136Z,version=java25,revision=97407c672fccc431e5eca6d4c1d008972b5f230f'
mc-aero-1  | + local oldState
mc-aero-1  | ++ shopt -po xtrace
mc-aero-1  | + oldState='set -o xtrace'
mc-aero-1  | + shopt -u -o xtrace
mc-aero-1  | [init] 2026-04-20 15:44:40+00:00 Image info: buildtime=2026-04-16T18:42:06.136Z,version=java25,revision=97407c672fccc431e5eca6d4c1d008972b5f230f
mc-aero-1  | + '[' '!' -e /data/eula.txt ']'
mc-aero-1  | + isTrue false
mc-aero-1  | + case "${1,,}" in
mc-aero-1  | + return 1
mc-aero-1  | + isTrue true
mc-aero-1  | + case "${1,,}" in
mc-aero-1  | + return 0
mc-aero-1  | + set +x
mc-aero-1  | + isTrue false
mc-aero-1  | + case "${1,,}" in
mc-aero-1  | + return 1
mc-aero-1  | + proxyArgs=()
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + proxyArgs=()
mc-aero-1  | + addToProxyArgs http.proxyHost ''
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + addToProxyArgs http.proxyPort ''
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + addToProxyArgs http.nonProxyHosts ''
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + export 'MC_IMAGE_HELPER_OPTS+= '
mc-aero-1  | + MC_IMAGE_HELPER_OPTS+=' '
mc-aero-1  | + fixJavaPath
mc-aero-1  | + which java
mc-aero-1  | + cd /data
mc-aero-1  | + export DECLARED_TYPE=NEOFORGE
mc-aero-1  | + DECLARED_TYPE=NEOFORGE
mc-aero-1  | + export DECLARED_VERSION=1.21.1
mc-aero-1  | + DECLARED_VERSION=1.21.1
mc-aero-1  | + isTrue ''
mc-aero-1  | + case "${1,,}" in
mc-aero-1  | + return 1
mc-aero-1  | + isTrue false
mc-aero-1  | + case "${1,,}" in
mc-aero-1  | + return 1
mc-aero-1  | + isTrue false
mc-aero-1  | + case "${1,,}" in
mc-aero-1  | + return 1
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + : ''
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + case "${TYPE^^}" in
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + log 'Resolving type given NEOFORGE'
mc-aero-1  | + local oldState
mc-aero-1  | ++ shopt -po xtrace
mc-aero-1  | + oldState='set -o xtrace'
mc-aero-1  | + shopt -u -o xtrace
mc-aero-1  | [init] 2026-04-20 15:44:40+00:00 Resolving type given NEOFORGE
mc-aero-1  | + case "${TYPE^^}" in
mc-aero-1  | ++ dirname /image/scripts/start-configuration
mc-aero-1  | + exec /image/scripts/start-deployNeoForge
mc-aero-1  | + resultsFile=/data/.run-neoforge.env
mc-aero-1  | + [[ -n '' ]]
mc-aero-1  | + mc-image-helper install-neoforge --output-directory=/data --results-file=/data/.run-neoforge.env --minecraft-version=1.21.1 --neoforge-version=21.1.227 --force-reinstall=false
mc-aero-1  | [mc-image-helper] 15:44:44.062 DEBUG : Using HTTP/1.1
mc-aero-1  | [mc-image-helper] 15:44:44.639 DEBUG : Requesting NeoForge version=21.1.227 for minecraft=1.21.1
mc-aero-1  | [mc-image-helper] 15:44:45.036 DEBUG : Fetching maven metadata for net.neoforged:neoforge from https://maven.neoforged.net/releases
mc-aero-1  | [mc-image-helper] 15:44:46.837 DEBUG : JSON FETCH: uri=https://maven.neoforged.net/releases/net/neoforged/neoforge/maven-metadata.xml headers=[user-agent: itzg/mc-image-helper/1.56.3 (cmd=install-neoforge), x-fetch-session: caaf81c5-b1a7-40c3-8e79-6b83681829b8, host: maven.neoforged.net, accept: */*]
mc-aero-1  | [mc-image-helper] 15:44:47.206 DEBUG : JSON FETCH: uri=https://maven.neoforged.net/releases/net/neoforged/neoforge/maven-metadata.xml status=200 OK
mc-aero-1  | [mc-image-helper] 15:45:17.313 ERROR : 'install-neoforge' command failed. Version is 1.56.3
mc-aero-1  | io.netty.handler.timeout.ReadTimeoutException: null
mc-aero-1  | + logError 'Failed to install NeoForge'
mc-aero-1  | + isDebugging
mc-aero-1  | + isTrue true
mc-aero-1  | + case "${1,,}" in
mc-aero-1  | + return 0
mc-aero-1  | + set +x
mc-aero-1  | [init] 2026-04-20 15:45:17+00:00 [ERROR] Failed to install NeoForge
mc-aero-1  | + exit 1
mc-aero-1 exited with code 1

[itzg]

Ah, you have network quality issues

mc-aero-1  | io.netty.handler.timeout.ReadTimeoutException: null

I'm guessing that's why you wanted to manually supply installer.

[Onseshigo]

Yes, that's why. Does it still tries to download something and fails because of it?

[Onseshigo]

Issue resolved by fixing network issues on my end and using automation method