I think you're mistaken. my modpack launches fine. in fact I can play the modpack, I can even start up a server, The issue is joining the multiplayer server and that is it. everything else is fine.
Every time I try loading into my server which has at least 200 mods on the server crashes and I get a message saying "{mod} ran into a problem". It works fine in single player but not on the server and I do not know why.