Automatic Weights creates empty vertex groups for Armature

Question

I have an armature and a mesh. Those 2 should move together like usual in rigging. The armuture's bones are all "deformable" and the mesh has its normals outside.

When I click the mesh, and then the armature > CTRL + P > Armature Deform With Automatic Weights it loads for a second, then I have the armature modifier and a bunch of vertex groups in the mesh data. When I try to pose the armature, the mesh doesn't move. Why is that? The vertex groups are all empty.

I don't know why that happens, it never was like this before. Also, i must have something to do with the mesh or armature because I just tried it with a default cube and 3 bone armature and it works no problem.

Please help

Model: https://file.io/tgO4Rx1VK3Mo

Answer 1

As the object is rather small it makes the mesh too dense to calculate the parenting correctly, so scale armature and mesh x 30 for example, parent again, and scale down the armature to its orginal 1:1:1 scale, and apply the scale of the mesh.