Asset is completly black

Hello everyone,
i hope somebody can help me by my problem in unreal engine 4. Im working on a environment project and have this very wierd issue with my assets. ( screen shots) How you can see the assets its turning completly black. in the viewport of the mesh it looks normal but as soon as i put the asset in the scene it shows black. i tried everything. I made a new lightmap, i converted it to static mesh, i tried every setting. The only thing which i tried and worked a little bit was i unabled the roughness map and the issue is gone but it just shows the diffuse map. So i tried to set down the roughness value lower but it dosnt worked eather. I hope somebody can help me here out because i really dont know what to do. And excuse me for my bad english.

Did you forget to add/bake lights?

Thank you for the reply. No i didnt. I tried with a point light, with directional light…nothing works. Actually it happened when i start to rebuilt the lighting. the only thing which works is when i start a complete new scene and put the asset in it, but when i bult the lighting again it shows black again.

Odd. Heres some guesses
A: It is 100% reflective and there are no reflection captures
B: There are some serious bugs on your end
C: UV errors

Try to add a capture first and see if it works.

Ok i will giv it a try+ Thank you you for your help!

Update: I tried all the davices youre givent to me and it was B. It seems unreal have a serious problem with my opacity map. the spheres have a glass material with a opacity map. when i uncheck the opacity map it shows the asset with the correct textures. I exportet the opacity map from substance painter. I dont know if there is some known isses similiar to this problem but ill try to find a solution. Again thank you very much for your help!