That first one isn't a hostname and it isn't a URL either.  So I don't think I could make that one work too easily.

The second two are being understood but there is some other problem.  Only I don't understand what it is yet.  404 Not Found is a strange error for an upload.

Could you try "https://blossom.primal.net" or "https://blossom.nostr.hu"  and see if they also give you a 404?