Converted to HDRP, everything is shiny and skybox is on every surface?

I just converted my demo house to HDRP.
I followed this tutorial: https://docs.unity3d.com/Packages/c...-definition@7.1/manual/Upgrading-To-HDRP.html

Unfortunately, every surface is now reflective and shows the Skybox.
If I turn off, or down the Directional Light (main lightsource), this stops. But then I have a dark scene. Any adjustment of increasing the Lux value to light it up, results in the included screenshot.

I'm using ProBuilder, and it's default HDRP material. I'm also using a bunch of other textures to test with the same result.

Please help

 

You need to set Directional Light to mixed and bake the lighting, maybe place reflection probe inside the room so that it doesn't reflect sky, set fixed exposure in post-porcess volume.

 

Unfortunately that didn't work either.
You can see the floor material is meant to be red, but is coming out silver too.

You can see in my second screenshot, the skybox floor is affecting the materials in my scene too. Even indoors, how do I fix this?

 

Hard to say without a screenshot of your material setup. What if you turn down the smoothness for the brick material? Is there a proper mask map with a smoothness texture? Also check the smoothness remap.