[Evolution] Helo command rejected: need fully-qualified hostname

[Franz Gratzer <franz gratzer fsfe org>]

I use Evolution 3.30.5-1.1 on a freshly set-up Debian 10 installation
with GNOME 3.30.2 on an IBM ThinkPad t400s.

I want to set-up an account that can only send mails. Receiving mails
works through a forward to an other mail address. This set-up worked
well in the past when I was using Evolution on Debian 9.

When creating the account in Evolution I should in theory select "none"
when asked for the the type of server which can receive emails.
Unfortunately when I do that I cannot send any mails. Instead I get the
error message: "Helo command rejected: need fully-qualified hostname".

Only when I chose one of the wrong options "POP" or "IMAP" for
receiving email I can actually send emails from this account. Of course
I get an error each time I pull my emails because the wrongly set
server doesn't provide the emails Evolution is looking for.

I am uncertain if this is a bug or if I did something wrong somwhere. I
tried the set-up many times and I always end up with one of the two
described behaviours.

Is this something I should report on gitlab.gnome.org?

Best,
Franz