Refraction with RTX and UE 4.25.3

hi, I’m going crazy trying to set up refraction with UE 4.25.3 and the automotive shader pack. I’ve replicated all the settings like in video tutorial for automotive from latyest Unreal Fest https://youtu.be/wNsgxgOk8Ss, but I still get a lot of noise any idea on how to fix it?