Gnus: Blocked message to gmail addresses

[H. Dieter Wilhelm]

Hello Gnus

now it's the second time that I couldn't send a mail to (multiple) gmail
addresses.  I've received a mail from the provider 1and1.de's mail
delivery system saying "dieter@duenehof-wilhelm.de" is blocked from
gmail with authentication problems (SPF and DKIM).  I checked sending
with the webmailer of 1und1.de and there sending to (some) gmail
addresses worked and then - strangely - resending the very same
problematic mail from Gnus seems to have work!?

Do you know such things?

Thank you

      Dieter

PS: The other problem I've (sadly since using Gnus) is that it archives
messages only to a local archive folder and doesn't "direct" them to the
providers mail server's "sent box".

;; sending messages
(setq message-send-mail-function 'message-send-it
      smtpmail-smtp-service  587 ; 2018-03-05 587 for starttls; 1&1: 587
      smtpmail-smtp-user "dieter@duenenhof-wilhelm.de"
      smtpmail-smtp-server "smtp.1und1.de")

(setq gnus-gcc-mark-as-read t)


(The smtp password is stored in ~/.authinfo.gpg)

-- 
Best wishes
H. Dieter Wilhelm
Zwingenberg, Germany