Trees become pink with The Lightweight Render Pipeline

I added the Lightweight Render Pipeline in my project, so all the trees and terrain became pink, corrected the terrain by adding a material to it and adding the LightweightPipeline shader. But the trees remain pink.

Reason: I need to use the Shader Graph (if I do not use The Lightweight Render Pipeline the materials get pink)

My steps:

1 - I created an Asset -> Create -> Rendering -> Lightweight Pipeline Asset 2 - I added to my project in Edit-> Project Settings -> Graphics at "Scriptable Render Pipeline Settings"

After that the whole scenario turned pink, so I used the option: Edit -> Render Pipeline -> Upgrade Project Materials to LightWeight Materials

Then my terre and the trees became pinks.

Someone can help me, because there are already many trees positioned in the scene.