Have you tried using Xenu?
I don't really know what you're trying to do but this is how I use Xenu. I take the list of backlinks that I got from the "backlink checker" addon. Then I put the links into Xenu and it tells me which links are dead. Then I take the dead links and check to see if their domains are available. I then look at the metrics to decide if they will make a good PBN.
Sorry, but how do I put this in Scrapebox? is there any brief way to explain this?