Beveling extruded plane + solidify

I am trying to create a simple beveled U shape with 2mm with for 3D printing.

Posted a question last weekend and received advices - thanks to everyone - but I am getting a different result. What do I need to do differently?

https://reddit.com/link/1osesgd/video/wsf2lat9670g1/player

This is what I expect to get - thanks to b_a_t_m_4_n:

https://preview.redd.it/jk4r8gpc670g1.png?width=1024&format=png&auto=webp&s=904ee6393bb10d0a77c5edde704f7f4ff99a720a