Datasmith scene very dark

I’m new to Unreal Engine but am attempting to create an arch viz scene via Datasmith and 3ds Max. I have imported my scene into UE4 fine, but once the import was done the light in the scene became very dark, including the space around the project, and the light source intensity doesn’t seem to make too much difference. When watching tutorials on lighting it doesn’t seem to be an issue for others. Just wondering if anyone has any idea what could be causing this? Or have experienced it themselves? I am using a directional light and have also tested point lights etc. with the same problem. Building the lighting doesn’t improve it also.