you can ask him on the 9front ml regarding this email issue, then he might give you an alternative channel to talk privately.

On Sat, Oct 17, 2020, 3:02 AM Andrew Hume <andrew@humeweb.com> wrote:
can stanley lieber contact me please (regarding an 8th edition manual)?
i can’t contact you via sl@stanleylieber.com (because of an SPF error),
so perhaps via another email address.

thanks