Have you tried downloading the DETR model directly from the facebookresearch repo on github 20 and loading it?
state_dict = torch.load("detr-r50-e632da11.pth")

To load the dict to the model this detr-demo-notebook 11 suggests building a class and instantiating it minimally (with just the number of classes) and then calling the method load_state_dict(), which is not defined in the notebook.
state_dict = torch.hub.load('facebookresearch/detr', 'detr_resnet50', pretrained=True)
detr.load_state_dict(state_dict) 

I’m still figuring out how to avoid a dict mismatch (‘missing keys’, etc.).