using imap: imap.%d might work, but you might never have a valid
ssl certificate that matches all hosted domains. So better use
the default kolab domain or fqdn

Esecially when chwala will create an extra session for the WOPI
editor/backend. WOPI will fail!

roundcube: use only mail,alias as login attributes in multidomain/hosted setup, make helpdesk role configurable