I cant join my firends one piece server because of an FML problem

[thedoodledoggo]

i dont know why it wont let me join him i ahve the mod and the java download thing and there is a red x that says imcompatable FML modded server

[ChampionAsh5357]

If it's incompatible, then you probably don't have all the mods on the correct versions to connect to the server. If you try to log in, it should tell you the versions of the mods you need to have.