Hello Michael,
In the same mesh viewer, be sure to set the “Lightmap coordinate index” to the right UV-map number.
Also keep in mind, that the auto generator looks at the first uv map created (in your case UV0) and if that uv-map isnt properly set up (cant have islands that overlap themselves, no partially inverted uv’s etc) it cant generate a decent uv-map for UV1.
Also, looking at that mesh… split it up, each of those buildings could be a seperate mesh, heck… every wall could be a seperate mesh.