Simple Landscape perfect in the editor but crash in multiplayer?

Hi, with a friend we are working on a multiplayer game. Every thing is working fine in the editor, we can connect and play together.
However when we try to play it from a Packaged version, we can connect to the lobby but once we load the main map we reciev this message :

My friend think the problem come from the Material “M_Landscape” I created for the Map.
but I don’t see anything special about this Material, it’s cheap (only 116 instructions) (and look realy good!)

I’m only using some mask on vertex normal to achiev a transition between Grass/Mud/Cliff there are some displacements for the cliffs but once again nothing to complicated :confused:
mask exemple:

displacement exemple:

Once again everything is working perfectly in the editor no error or anything but it only crash on the packadged version ?

Any ideas ? Could it comes from the Landscape_Component instead of the Lanscape_Material ? Is there any problem in the way we load the level in the blueprint ?

Any suggestions anybody ? :slight_smile: