socket does not show up in blueprint

Hi,

ive added a socket to this mesh:

dragged that mesh into my blueprint:

but on the right, when i enter socket it does not show “first”:

i can select Shape_Trim_90_Out or Static Mesh, first as socket does not exist.

Why?
Already saved the mesh multiple times, re added it to the viewport, but no luck.

never mind, does not show up in blueprint but can be used in code:
AttachActors(this, ChildActor, TEXT(“first”));