Dedicated Server Troubleshooting

This is a collection of common problems and solutions for not working modded dedicated servers.

TL;DR

1. Make sure BepInEx loads. Check that the log under BepInEx/LogOutput.log has been recreated since the last server start-up. If not, no mods have loaded on the server at all
2. If you use a server host and there is a BepInEx toggle somewhere, make sure to turn it on. If there is not a BepInEx toggle, but one for Valheim Plus you must turn that on. If you do not want to use the V+ mod, delete the ValheimPlus.dll or install Valheim Minus.
3. If you start from R2MM/TMM you need to edit the start_headless_server.bat inside the Steam Valheim Dedicated Server folder and append %* at the line where the server is launched. However, be aware that the mod manager uses the same folder location for both the server and client, so if you use the mod manager to launch both you may run into issues with some mods.

Failed to Connect

If you get this error window, it probably means you could not reach the server. Make sure the server is running and the URL/IP address is correct. If you switched between crossplay and non-crossplay, Valheim sometimes remembers this and wants to connect to the old server. Remove the server from your recent connection list and add it again refresh it.

Blackscreen After Connection Attempt

This can mean a mod uses an outdated ServerSync version internally. You can try to use the ServerSyncFix by Jere, which patches and write the causing mods to your console. Be aware that this is only a short term workaround, the causing mods are no longer supported by their authors and could break at any time.

Mods are not Loading

Many mods only need to be enabled on the client but some have to be installed on the server to synchronize configs or version check. This means even if you were able to connect with some mods, it does not imply that mods have been loaded on the server.

To tell if a mod has loaded on a server, check the log file at BepInEx/LogOutput.log. It is a text file that writes [Info : BepInEx] Loading [ModName 1.0.0] for every mod that was successfully found in the file and loaded. Be sure that the file was generated currently by either looking at the last modification time or shutting the server down, deleting the file and rebooting the server. If this file does not appear, BepInEx hasn't loaded.

Secondly, make sure no errors are appearing as these could cause further issues and prevent mods from working correctly.

BepInEx is not Starting

Many server host support mods, but require you to toggle on a setting for the BepInEx mod loader. You may have added your mod files to the server but they will not start unless this toggle is on. A common issue with some Valheim server hosts is that ValheimPlus must to be enabled in order to start BepInEx. Even if BepInEx is manually installed this can be the case. If you have a web interface and a V+ switch, make sure to turn it on and restart the server. If you don't want to run V+ you can delete the ValheimPlus.dll or install Valheim Minus. This is no offence to the ValheimPlus mod itself but the host companies, nobody should be forced to use a mod they don't want.

Also make sure BepInEx is up to date. It can be downloaded from here BepInExPack Valheim. Do not use the BepInEx release from GitHub as it isn't configured to work with Valheim.

R2MM/TMM is Launching Vanilla

The Valheim script to start a server cuts off all additional parameters set by the mod managers. Edit the start_headless_server.bat inside the Steam Valheim Dedicated Server folder and append %* at the line where the server is launched:

Specific Valheim Server Hosts

No information at this time.