diff --git a/plugins/UM3NetworkPrinting/src/Network/SendMaterialJob.py b/plugins/UM3NetworkPrinting/src/Network/SendMaterialJob.py
index 8de732e2a6..5637f388c1 100644
--- a/plugins/UM3NetworkPrinting/src/Network/SendMaterialJob.py
+++ b/plugins/UM3NetworkPrinting/src/Network/SendMaterialJob.py
@@ -68,10 +68,10 @@ class SendMaterialJob(Job):
     #   \param materials_to_send A set with id's of materials that must be sent.
     def _sendMaterials(self, materials_to_send: Set[str]) -> None:
         container_registry = CuraApplication.getInstance().getContainerRegistry()
-        material_manager = CuraApplication.getInstance().getMaterialManager()
-        material_group_dict = material_manager.getAllMaterialGroups()
+        all_materials = container_registry.findInstanceContainersMetadata(type = "material")
+        all_root_materials = {material["base_file"] for material in all_materials if "base_file" in material}  # Filters out uniques by making it a set. Don't include files without base file (i.e. empty material).
 
-        for root_material_id in material_group_dict:
+        for root_material_id in all_root_materials:
             if root_material_id not in materials_to_send:
                 # If the material does not have to be sent we skip it.
                 continue
@@ -128,20 +128,18 @@ class SendMaterialJob(Job):
     @staticmethod
     def _getLocalMaterials() -> Dict[str, LocalMaterial]:
         result = {}  # type: Dict[str, LocalMaterial]
-        material_manager = CuraApplication.getInstance().getMaterialManager()
-        material_group_dict = material_manager.getAllMaterialGroups()
+        all_materials = CuraApplication.getInstance().getContainerRegistry().findInstanceContainersMetadata(type = "material")
+        all_root_materials = [material for material in all_materials if material["id"] == material.get("base_file")]  # Don't send materials without base_file: The empty material doesn't need to be sent.
 
         # Find the latest version of all material containers in the registry.
-        for root_material_id, material_group in material_group_dict.items():
-            material_metadata = ContainerRegistry.getInstance().findContainersMetadata(id = material_group.root_material_node.container_id)[0]
-
+        for material_metadata in all_root_materials:
             try:
                 # material version must be an int
                 material_metadata["version"] = int(material_metadata["version"])
 
                 # Create a new local material
                 local_material = LocalMaterial(**material_metadata)
-                local_material.id = root_material_id
+                local_material.id = material_metadata["id"]
 
                 if local_material.GUID not in result or \
                         local_material.GUID not in result or \