My Mesh Turn Black After I Turn On Two Side on UNREAL 5

Hi, I have .fbx file that I imported to Unreal 5 from Blender. At my first project that i’ve deleted, when I turn two side, it was working without any problem. I’m a noob so first time when I saw my mesh model (It’s a leather tarp) gone when I go the other way around I was panicked. Then I saw tutorial that I just need to turn on the Two side. And it worked!.

Then I delete the project because my hardisk is dont have more storage. Then I create new project. Then when I import the .fbx and turn on the two side, suddenly its turn black.

I’ve already change the SourceLightmassIndex into 1, but with no avail.

Is there anybody can help me or any tutorial outhere? thank alot! (I’m really noob in 3D, so when at first attemp it worked and now it doesnt, it really frustated me) :((