Can't say I've had any other reports of that happening. What other mods are you running and are you re-rolling the world when you create the game?

Respec Potion, Many Monsters, Synergies Mod, Awesome Classes, Sword, Warglaives of Azinoth. And we have tried rerolling and not rerolling

Same thing happened to me. My friend and I were running SynergiesHighLoot, SynergiesMod, Endless Dungeon (In that order, top to bottom).

Originally posted by Neuromancer:

Same thing happened to me. My friend and I were running SynergiesHighLoot, SynergiesMod, Endless Dungeon (In that order, top to bottom).

Recently I found my game crashing from only having Synergies mod whenever a friend joined. That may be the problem.

Although my issue involves having Essentials installed.

Originally posted by Wayback:

Can't say I've had any other reports of that happening. What other mods are you running and are you re-rolling the world when you create the game?

In my case, it was only Endless Dungeon and Synergies. From top to bottom in that order.
My partner and I both started new characters with said mod so I don't think we could have fixed it by rerolling.

maybe the other players (as posted by aquinius) didnt have the endless dungeon mod?

She had the same mod sets, actually.

is it still a thing?

same problem, game crash when this mod+synergies active, but If I and my friend turn off endless dungeon, everything OK

I can confirm that this mod does not currently run with synergies in multiplayer.

YEARS LATER but who knows if it was answered :P LAN is the best for dodging this, but researching each MOD you use and the placement the creator claims is best is a nice way to start guessing around top to bottom importance. Only other thing I can think of is it directly clashes with another MOD you are using; which most likely would be from a merge MOD that may or may not have a similar or the same MOD possible.