Mods and multiplayer not very compatible

[Mithrandir]

There are some mods that work but don't allow other players to join, the bigger the size of the mod the higher the chance of this happening.

on a sidenote: is it me or has the whole multiplayer experience gone wonky when you want to join? (not finding your friends game for example)

[Huren Ogeko]

Mods are not officially supported by the game
what we have is a community created mod platform that does well in single player less so in multiplayer and even less so in dedicated servers. Improvements will probably be made but since the mod manager is made by the community which is working outside coffee stain what they can achieve is limited by the constant moving target of a developing game. Now that 1.0 is out maybe the biggest changes to the game will be behind us and better support for more complex setups will come.

when it comes to multiplayer its best to keep it as vanilla as possible

[Zak]

Mod's size doesn't matter. Some mods work with multiplayer and some don't. All players who join must have the same mods and the same version of mods. Simple as that.

If you want to have good... um.... better multiplayer experience with multiple players then run a dedicated server. Most major mods support the server.

Like Huren Ogeko said: multiplayer is "safest" with no mods unless you run a server and put in the effort to manage the mods.

PS. The size of the game matters though for multiplayer, modded or not, even the server will struggle with large, late game.