Removed "sslcacerfile = /etc/ssl/cets/ca-certificates.crt" on line 10 - it was pointing to non-existant directory "cets" instead of "certs" - this setting is overwritten later with correct path therefore no errors would register.

configuring offlinemap to get emails from Microsoft Exchange via Davmail I run into a problem, which could be fixed by changing "port" to "remoteport" in the remote-part of the config.
See also here:
https://github.com/OfflineIMAP/offlineimap/blob/master/offlineimap.conf
# This option stands in the [Repository RemoteExample] section.
# Specify the port.  If not specified, use a default port.
#remoteport = 993

If running offlineimap it will show the following warning message (tested when using GMAIL)...

 XOAUTH2 authentication failed: AUTHENTICATE command error: BAD ['Client aborted AUTHENTICATE command.
<randomstring>']. Data: DIEF2 AUTHENTICATE XOAUTH

... and then continue with the download/sync of emails.
You can get rid of the warning message, when adding auth_mechanisms = LOGIN .offlineimaprc in the <...>-remote section.

This is first working version of an added login query to the account
creation process. It fixes the first part of #6, but there still needs
to be more testing for the second part of that issue, which concerns
creating accounts with domains not listed in domain.csv.