Yes, there are intermittent problems with Dan.com landers:
https://www.namepros.com/threads/dan-com-domain-marketplace-official-thread.1148567/page-251#post-9172129
If you're "developing a website to sell a series of informational books", why would/should you use (or especially pay extra for) bookname.anything?
To be honest, selling informational books is hard. I think they are best used as lead magnets...
prompt 1 (copied) ->
[...]
No advice as to where to sell it.
prompt 2: For option 4. Where could I sell it?
prompt 3: Don't you know about the recent change to GoDaddy Auctions? No member to member listings anymore.
prompt 4: Why...