Can't bake scene

After some hours of baking I got message “Could not allocate memory”.
I have ~20 light sources.
How can I solve it?

I can see that some light sources are baked successfully. Should I delete them and repeat trying?

Here is my settings:

Clear GI Cache in edit → preferences.

Then, Copy all your objects in your hierarchy into a new scene and bake again.

This solved some major GI issues for me.