Static Mesh object has overlapping UVs

The erros are:
Static Mesh object has overlapping UVs
Static Mesh lightmap UV are overlapping by 50%
The color of the texture of the maze is white and it has became black!!!
please help me

2018-04-04 (1).jpg

I had the same error message as the op and I followed your instructions which were really helpful but not completely satisfying. The textures/uv-/lightmap of my mesh do look better now by increasing the lightmap resolution which now is at 4096 but there are still some artifacts showing up. Also there were added some new ones.

I don’t think that still increasing the lightmap resolution to fix this artifacts will be performant. What else can I do to get a better looking lightmap?

I am having the same error log still couldnt find a solution.

However, to solve dark shadows on your assets as temporarily please follow,

pick your asset or mesh > search light on details panel > uncheck and check the overriden light map res

with that you will be able to see the shadows corrected.
If anyone finds how to fix the error log as the poster shared above, please help from here.