I'm locking this thread due to necro, but before I do I will mention the cause of this, for anyone that might find it in search.
If you view too many deleted saves in a short time, the website will consider you to be "scraping". This most often happens if you look for save IDs sequentially. We don't want bots scraping saves, so fake 404 errors when this happens.
The implementation is a bit wonky, so if you view a fake 404 save, it also counts as "save scraping" and will cause the fake 404 saves to compound further. Just wait several minutes and you should be good. This issue extremely rarely comes up, besides for bots / scrapers.