Invalid/Non-functioning E-mail No advertised SMTP servers are accepting mail

I tried to reinstate a former member. I moved the entry for Kevin Chapman ACB from Former Member list (where his email was madpiper@mountprospect.com) to Members List. I modified his name to match as entered in the Roster on Toastmasters.com (J Kevin Chapman DTM) and changed his email to match as entered in the Roster on Toastmasters.com (jkchapman@mountprospect.com). I saved my change and got a "Invalid/Non-functioning E-mail: jkchapman@mountprospect.com (No advertised SMTP servers are accepting mail.)" error.
What did I do wrong? Not saving the entry moved from Former Member to Member before I tried to modify it?

I see instruction with the message: "However, you only need to enter each person's name below--e-mail address & phone are optional" but if I leave off an email, a 'noemail-1589056757@toastmastersclubs.org" is generated.

Then I see these directions on Membership Management page say
" An E-mail address should be entered if the person has one, but is not technically required."
' • This will allow current members ONLY to select their name from the list of members and authenticate via e-mail.
• Once authenticated, they can update their own basic information via their member profile."

I always assumed that Admin, or one of the officers given access to Membership management, had to enter person's name and at least email address (from Roster after application entered) so that person is included in the Members-1645 list. I never thought to require them to update their Profile immediately. (I suspect many newer members haven't touched their Profile, unless it was to add a photo or TI logo.)

BTW, J Kevin Chapman belongs to another D30 club Career Communicators which does have a FTH website. Does his email address on that site match the one I tried to enter? (Can a dual member use different email addresses or even names sharing the same TI member ID?)

Please stop over thinking this.
His email doesn't work because it is hosted in a datacenter that spams FTH.
I have allowed the mail server for mountprospect.com

Thanks Brian for explaining it to me. And correcting Kevin's email in out Members list (unless he did it himself through his Profile last night. (Chapman has been using the same email address in Career Communicators club too.)
(A quick check shows the village's official website (and thus email server) is MountProspect.org. The only other organization or individuals using MountProspect.com is American Legion Post 525 of Mount Prospect; and someone at the chamber of commerce whose private email also uses the same server. Kevin still uses, or used to use, madpiper@mountprospect.com for his Bagpiping hobby.