Substack Publications Issues

[solacessyn8468]

Hello I've been trying to read more news on my ereader and I've been slowly trying to use Calibre to help with this. (It's slow going because I still don't totally understand the whole RSS Feed thing). Recently I've been trying to use the built in recipe for substack to read some of the publications I'm subscribed to and I'm struggling. I can't seem to get several of the publications to work, Calibre keeps throwing up an error every time I try to add them. I tried going in to the actual recipe and it still isn't working. I can't figure out if this is like a problem with the publication itself or if I'm just doing it wrong. I would appreciate some help