Arma 3 server problems

Common Arma 3 server problems and how to fix them. Mod settings live on your Startup page. See Arma 3 settings.

Players get kicked or cannot join because of mods

Why it happens: Arma 3 requires players and the server to run the same mod versions. If a mod updated on the Workshop but not on the server (or the other way round), players are refused.

How to fix it:

1. Make sure Automatic Updates (UPDATE_SERVER) on the Startup page is set to 1.
2. Restart the server so it checks for mod updates.
3. Ask players to update their mods in the Steam Workshop and restart the game.
4. If it still fails, set [Repair] Validate Server Files (VALIDATE_SERVER) to 1 for one start, then set it back to 0. It makes startup slower.

Client and server mod lists do not match

Why it happens: The server only loads the mods from your modlist file and Additional Mods. Players must load the same required mods.

How to fix it:

1. Export your modlist from the Arma 3 Launcher as an HTML file.
2. Open Files and upload it to the server’s root folder.
3. On Startup, set Modlist File (MOD_FILE) to that exact filename (default is modlist.html).
4. Restart the server and check the Console for each mod loading.

Modlist HTML is ignored or no mods load

Why it happens: The filename does not match, the file is in a subfolder, or the file was exported wrongly.

How to fix it:

1. In Files, check the file is in the root folder, not inside another folder.
2. Check the name matches Modlist File exactly, including capitals and the .html ending.
3. Re-export the list from the Launcher and upload it again.
4. Restart and read the Console for errors.

Mods fail to load or files are not found

Why it happens: Arma on Linux is case sensitive. Mods copied from Windows often have capital letters in file names.

How to fix it:

1. On Startup, set [Repair] Make Mod Files Lowercase (MODS_LOWERCASE) to 1.
2. Start the server once, then set it back to 0.
3. Make sure folder names in Additional Mods use no capitals and no spaces.

Signature or key errors (players kicked by signature checks)

Why it happens: With signature checking on, every mod the player loads needs its .bikey in the server’s keys folder. A missing or outdated key blocks the player.

How to fix it:

1. Update the mod on the server (restart with Automatic Updates on).
2. The server normally copies each mod’s .bikey into the keys folder itself. In Files, open keys and check the mod’s key is there.
3. If a player runs a mod the server does not have, they need to remove it, or you can list it under [Advanced] Optional Client-Side Mods (OPTIONALMODS), in @workshopID form separated by semicolons, e.g. @123456789;@987654321;.

Server-side mod makes players fail to join

Why it happens: A mod that only needs to run on the server was loaded as a normal mod, so clients are asked to have it too.

How to fix it: Move it from Additional Mods to [Advanced] Server-Side Only Mods (SERVERMODS). Clients do not need these when signature checking is enabled.

Server does not appear in the server browser

Why it happens: New servers can take a few minutes to show up. Passwords, ports, and long or mismatched mod lists also hide or block a server.

How to fix it:

1. Wait a few minutes after the status says Online.
2. Try direct connect using the address and port on the Network page. See Network and ports.
3. Remove Server Password temporarily to test.
4. If direct connect works but the list does not, open a ticket so we can check the ports.

BattlEye error or “Kicked by BattlEye”

Why it happens: BattlEye can block players with outdated clients, modified files or a blocked BattlEye service.

How to fix it:

1. Ask the player to restart Steam and Arma 3 and let BattlEye update.
2. Verify the game files in Steam.
3. Check the player’s antivirus or firewall is not blocking BattlEye.
4. Some mods do not work with BattlEye. Check the mod’s own notes.

Server crashes or runs out of memory with many mods

Why it happens: Big modlists and large missions use a lot of memory. When the plan limit is reached, the server is stopped.

How to fix it:

1. Watch the memory graph on the Console.
2. Remove mods you do not need.
3. Lower Max Players (MAX_PLAYERS).
4. See Out of memory. A bigger plan may be needed. See Upgrade.

Creator DLC (CDLC) will not load

Why it happens: CDLC files must be downloaded, then loaded by folder name.

How to fix it:

1. Set Download Creator DLCs (CDLC) to 1 and restart so it downloads during the update.
2. Add the CDLC folder name to Additional Mods, for example vn; for Prairie Fire.
3. Players must own the CDLC too.
4. If the update fails, open a ticket with the Console output.

Where are server.cfg and basic.cfg?

Why it happens: Arma 3 keeps server rules in server.cfg and network tuning in basic.cfg. On this panel, some values may be rewritten on each start.

How to fix it:

1. Open Files and find server.cfg.
2. Edit the settings the game documents, such as the mission list, then save.
3. Values covered by Startup variables (password, max players) should be changed on Startup, or they may be overwritten.
4. Restart the server.

Extra startup parameters cause a crash

Why it happens: A wrong or unsupported flag in Extra Startup Parameters (STARTUP_PARAMS) can stop the server from starting.

How to fix it:

1. On Startup, put the value back to -noLogs.
2. Save and start the server.
3. Add flags one at a time using the Arma 3 startup parameters list.

Server stuck updating or Steam download fails

Why it happens: Steam download hiccups, or a full disk from many mods.

How to fix it:

1. Check your disk use. See Disk full.
2. Restart the server to retry the update.
3. Use Validate Server Files once if files look corrupt.
4. If it repeats, open a ticket.

Headless client crashes or spams the Console

Why it happens: Headless clients (HC) are for advanced use, add extra load and only help with missions written for them.

How to fix it:

1. Set [Advanced] Headless Clients (HC_NUM) to 0 to turn them off.
2. If you keep them, enable Clear HC Profiles Cache on Startup (CLEAR_CACHE) and keep HC Hide Console Output on.
3. If the server has a password, headless clients need it too.

Still stuck?

Open a ticket or ask on Discord. See Contact support.