custom node: return SceneTextureLookup(uv,14,false) not working

Hello there, in Post Process material the hlsl code in a custom-node (“return SceneTextureLookup(uv,14,false);” always says [SM5] /Engine/Generated/Material.ush(1410,8-46): error X3004: undeclared identifier ‘SceneTextureLookup’. In Window → HLSL Code there is a correct function defined:
float4 (float2 UV, int SceneTextureIndex, bool bFiltered)
{…}

Other functions work too… So either i miss something really badly or there is something wrong with this shader function. I experienced this problem in 4.21 and 4.19.2

Maybe someone can help me with it.

regards

Gotta use scene texture material expression in your graph before the custom node.

Already got it to work. Might be too late yesterday :). Thank you.

Hello , could you please tell me how you solved the issue?
Thank you!!

Why is this the case? The function in HLSL looks like it should be accessible.