I'm trying to get an outline shader to work in Blender 2.8/2.9 but the results are not like expected. After I tried it several times on my own, I followed this tutorial:
https://www.youtube.com/watch?v=hp4V-9oFmnM
It also includes an examplary .blend file:
https://drive.google.com/file/d/1EffSaNaOWk53MCzr2RFK8SBHegBE1UmP/view
First, the results I get never yields a proper outline. Instead it either appears transparent or makes the object completely black. Results are the same in viewport and when rendering. Results seem to change arbitrarily when switching from Eevee to Cycles but both do not work. It seems like the backface of the solidified object is either not transparent or the whole solidified object is transparent.
Here some images from viewport in render view:
With Eevee

These are the steps of the tutorial which I also followed:
- Create object and assign arbitrary material to it
- Add solidify modifier, increase thickness, invert normals and assign second material slot
- Create an outline material, in this case it is just an Emission BSDF of black color assigned to surface of the material output
- In material settings, apply Backface Culling
Here the graphs for the outline shaders I tried:

In the example, Blend mode is set to opaque, but it doesn't make a difference if I switch it to Alpha, same for Shadow mode.
Here an example of the settings I used:

I tried everything but nothing works. Do I miss a secret setting somewhere? Rendering is done on CPU only - is it maybe a general hardware/software issue?

