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How to Troubleshoot Common Problems on Your Arma Reforger Server
Arma ReforgerArma ReforgerTroubleshoot Problems

How to Troubleshoot Common Problems on Your Arma Reforger Server

Find and fix common problems on an Arma Reforger server – startup errors, server browser, versions, mods, crossplay, RCON and admin login

8 min read
Oct 2, 2026

If your Arma Reforger server does not start, does not show up in the server browser or players cannot join, the cause is usually one of a few typical problems. This guide shows you the most common problems, their cause and the matching solution.

Check the logs first

Almost every problem leaves traces in the server output. Before you change anything, take a look at it:

  • Console: In the dashboard you can see the server output live. The last lines before a crash or abort are usually the important ones.
  • Log files: The complete logs are located on your server in the folder /profile/profile/logs/. How to find and read them is shown in Read Server Log.

Server does not start after a change to config.json

Cause: The config.json is no longer valid JSON – a single missing or extra comma, a missing bracket or a missing quotation mark is enough.

If the server starts but a setting has no effect, the spelling is often the cause: the server distinguishes between upper and lower case in the parameters in config.json. A key with the wrong spelling, e.g. vonDisableUI instead of VONDisableUI, is a different parameter for the server and does not work as intended.

Solution:

  1. Stop the server
    Stop your server via the dashboard.

  2. Connect via SFTP
    Connect to your server via SFTP.

  3. Check config.json
    Open the file config.json in the root directory of your server and copy its content into a JSON formatter like JSONLint. The formatter shows you the line that contains the error.

  4. Fix the error
    Correct the reported spot and also check the spelling of the keys you changed. You can find the correct spelling in Configure Server.

  5. Start the server
    Save the file and start your server. Check in the console whether it now starts without errors.

Server is not shown in the server browser

Cause: In the settings, Visible in Server Browser is set to false. Also check in the console whether the start has finished before you look for the server in the list.

Solution:

  1. Open dashboard
    Open the dashboard of your server.

  2. Open settings
    Navigate to the Settings.

  3. Enable visibility
    Set the Visible in Server Browser field to true.

  4. Restart the server
    Save the setting and restart your server. Wait until the server has fully started in the console, then refresh the server list in the game.

Version mismatch when joining

Cause: Players get a message about a mismatching version when joining, or the server stays on an old version although the game has already been updated. Usually Auto Update is set to 0 in the settings – then the server is not updated on start.

Solution:

  1. Open dashboard
    Open the dashboard of your server.

  2. Open settings
    Navigate to the Settings.

  3. Enable Auto Update
    Set the Auto Update field to 1.

  4. Restart the server
    Save the setting and restart your server. The server is brought to the current version in the process.

You can find more about this in Control Automatic Updates.

Mod download fails and the server does not start

Cause: A modId is misspelled or an entered version does not exist (anymore) in the Workshop. By default, every listed mod is required for the server to start – if it cannot be loaded, the server does not start.

Solution:

  1. Stop the server
    Stop your server via the dashboard.

  2. Connect via SFTP
    Connect to your server via SFTP.

  3. Check mod entries
    Open the file config.json and compare the modId and version of each mod with the information in the Arma Reforger Workshop. You can see which mod is affected in the console or in the server log.

  4. Start the server
    Save the file and start your server.

Mark optional mods

You can mark mods that your server can also run without as optional with "required": false. If such a mod cannot be loaded from the Workshop, the server automatically removes it from the list, writes a warning to the log and starts anyway.

Bring mods to the latest version

If a mod has a fixed "version" in config.json, your server stays on exactly this mod version – even if a newer one has long been released in the Workshop. If you want to use the latest version, you have two options:

  • Update the version: Enter the current version number from the Arma Reforger Workshop – just as Change Scenario describes for workshop scenarios.
  • Leave out the version: The "version" parameter is optional. If it is missing, the server automatically uses the latest version of the mod.
  1. Stop the server
    Stop your server via the dashboard.

  2. Connect via SFTP
    Connect to your server via SFTP.

  3. Adjust the mod version
    Open the file config.json and update the "version" of the mod in the "mods" section or remove the line completely.

  4. Start the server
    Save the file and start your server.

How to add mods is shown in Add Mods.

Console players cannot join

Cause: The dashboard enables crossplay automatically on every server start. If players on Xbox or PlayStation 5 still cannot join, the mods of your server can be the cause: not every mod is available on every platform.

Solution:

  • Check in the Arma Reforger Workshop whether all mods of your server are available on your players' platform, and remove mods that are not.
  • If in doubt, briefly test without mods whether console players can join then. This shows you whether the mods are the cause.
  • Keep Battle-Eye enabled (true) in the settings. Without BattlEye, your server does not appear in the server browser on PlayStation 5.

You can find more about this in Enable Crossplay.

RCON does not work

Cause: RCON only starts if a valid password is set. The password must be at least 3 characters long and must not contain spaces – otherwise RCON does not start.

Solution:

  1. Open dashboard
    Open the dashboard of your server.

  2. Open settings
    Navigate to the Settings.

  3. Adjust RCON password
    Enter a password with at least 3 characters and without spaces in the RCON Password field, e.g. MyRconPassword123.

  4. Restart the server
    Save the setting and restart your server.

How to connect with RCON afterwards is shown in Use RCON.

Admin login with #login fails

Cause: The admin password does not support spaces. If the Admin Password field contains a space, logging in with #login does not work.

Solution:

  1. Open dashboard
    Open the dashboard of your server.

  2. Open settings
    Navigate to the Settings.

  3. Adjust admin password
    Enter a password without spaces in the Admin Password field, e.g. MyAdminPassword123.

  4. Restart the server
    Save the setting and restart your server.

How to log in as admin afterwards is shown in Become Admin.

Server shuts down when the backend connection is lost

Cause: If the server loses the connection to the Arma Reforger backend, it shuts down automatically by default. This is triggered by errors in the so-called room requests – the server's requests to the backend.

Solution: With the disableServerShutdown parameter in the "operating" section, you prevent the server from shutting down in this case.

  1. Stop the server
    Stop your server via the dashboard.

  2. Connect via SFTP
    Connect to your server via SFTP.

  3. Add parameter
    Open the file config.json. If there is no "operating" section yet, add it at the top level – e.g. directly after the "game" section, separated by a comma:

    "operating": {
      "disableServerShutdown": true
    }
    

    If the "operating" section already exists, only add the line "disableServerShutdown": true there.

  4. Start the server
    Save the file and start your server.

Wrong player count in the server browser

Cause: If the player count shown in the server browser differs from the actual one, the lobbyPlayerSynchronise parameter in the "operating" section may be set to false. When it is enabled, the server regularly reports the list of connected players to the backend – exactly this fixes the discrepancy between the real and the reported player count.

Solution: The parameter is enabled by default. This is how you check whether it has been switched off in your config.json:

  1. Stop the server
    Stop your server via the dashboard.

  2. Connect via SFTP
    Connect to your server via SFTP.

  3. Check lobbyPlayerSynchronise
    Open the file config.json and check whether the value "lobbyPlayerSynchronise": false is set in the "operating" section. If so, set it to true or remove the line.

  4. Start the server
    Save the file and start your server.

Server is overloaded or lagging

Cause: Many players, AI units, large view distances or extensive mods can put a heavy load on your server. The result is stuttering, delays or a low server FPS value.

Solution: How to reduce the load – e.g. via Max FPS, view distances or an AI limit – is shown in Improve Performance.

Written byEmeraldHost Team
Last updated on Oct 2, 2026 Edit on GitHub

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