I've unwrapped UV and set lightmap coordinate index correctly, lightmap resolution is high enough, but object still get black after build light

Development Rendering
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I think I’ve found the the temp solution

Error message:

“Warning WallA01 has degenerate tangent bases which will result in incorrect shading.”

Here’s the youtube solution:

It seems like a bug, you just have to leave light map channel to a number that it shoud not...