Dedicated Server Crashing InitDefaultMaterials() Line 435

I can build a dedicated server with no problem, but it crashes when I run it. An assert fails at UMaterialInterface::InitDefaultMaterials Line 435. It can’t find the WorldGrid material. This is a modified version of 4.18 because I fixed a couple of VR related bugs. I attached the server text
Any Ideas?

I think i get a similar error on a non modified ue4.18 Assertion failed: GDefaultMaterials[Domain] != nullptr [File:D:\engines\epic\UE_ -