I've occasionally encountered workflows that contain nodes associated with specific cloud services or environments, such as Automatic1111.
I've also found custom nodes that the author has removed because they've opted to make them paid.
Some workflows load correctly, highlighting the missing module in red, while others display a message indicating the missing node and fail to load. This happened to me in this case:
Here's a solution:
Custom fake nodes. Download the repository and follow the steps to create the nodes you need to simulate, without losing the connections, so you can replace them with working nodes.