The Modpack Manager installs premade CurseForge packs in a few clicks. It is the easiest way to get a modpack running, and the path most players want. The Modpack Manager comes with every WinterNode Minecraft server hosting plan, so you can install a CurseForge pack straight from the Game Panel.

Install your modpack

The Modpack Manager pulls thousands of packs straight from CurseForge and installs them in a few clicks.

In the Game Panel, open Tools > Modpack Manager.
Search for your pack and click Install. Choose Install Only to keep your existing world and files, or Format Server to wipe everything and start fresh.
Set the right Java version for your pack’s Minecraft version - the panel doesn’t set this for you, and the wrong version crashes the server on startup. See Java Version Selection.
Start your server.

Common Issues

Most common first.

Client-side mods crashing the server

Some mods only run on the client (your PC) and will crash a server if installed there. This is the most common reason a modded server will not start.

You will see this in the log:

[main/FATAL] [ne.mi.fm.lo.RuntimeDistCleaner/DISTXFORM]: Attempted to load class
net/example/mod/mixin/SomeClientMixin for invalid dist DEDICATED_SERVER

The phrase for invalid dist DEDICATED_SERVER means a client-only mod tried to load on the server. To fix it: find the mod name in the class path, remove that jar from the mods/ folder, and repeat for any others. It is safe to remove them; players keep them on their own end.

Common client-only culprits: shader loaders (Oculus, Iris, OptiFine, Embeddium), FPS and rendering mods (Dynamic FPS, Entity Culling), HUD and minimap mods (Jade, WTHIT, Xaero’s Minimap), and visual effects (Falling Leaves, Sound Physics).

Server will not start (wrong jar)

If the server runs as vanilla, or reports Unable to access jarfile, the Server Jar File is set wrong. Point it at the installed forge-*.jar or server.jar, not minecraft_server.*.jar and not the -installer.jar (a Forge installer won’t run as a server). If there is no modloader jar at all, the pack did not include one: install the matching modloader with the Edition Installer.

Can’t connect after installing

If the server starts but players get Connection Lost or an error on join:

Client version mismatch: players must run the exact same pack and version as the server.
Faulty install: if the log shows missing mods or classes, stop the server, delete the mods/ folder and modpack configs, and reinstall through the Modpack Manager (or manually).
Large-pack timeout: big packs can kick players before they finish loading. Add Packet Fixer (1.15 to 1.21+) or RandomPatches (1.12 to 1.19) to the server only to raise the timeout.

Uninstalling a Modpack

Switch to a different modpack

Archive your current files first so you can switch back later. See Update or Switch Your Modpack.

Go back to an unmodded server

Take a manual backup if you want to keep your world or configs.
In the Game Panel, go to Advanced > Server Actions and pick Paper or Vanilla from the Edition dropdown.
Enable Format to remove all modpack files, then click Install Different Edition.
Start your server.

For more on the Edition Installer and available server software, see Using the Edition Installer.