Hello,
I am the MS Exchange 2016 operator in my (Active Directory based) organization. There are several authorative maildomains created on the (DAG) Exchange servers. The organization is using Office 2016. An Outlook user has a personal mailbox and two extra mailboxes configured in the Outlook profile. Because it is not possible (and not supported/recommended by MS) to have multiple Exchange accounts in Outlook, the user's mailprofile is configured like this:
* Personal mailbox (personal@mainmail.com): MS Exchange account, main data file account in Outlook profile
* Extra mailbox1 (mail@mail1.com) : IMAP account, main account in Outlook profile
* Extra mailbox2 (mail@mail2.com) : IMAP account
Prerequisites: All mailaccounts should be configured as 'real' accounts (shared mailboxes are not an option due to some restrictions it harbours), personal mailbox must be an Exchange account
Sending mail directly from the Outlook client results in the following situations (works like it should):
* User creates mail while in the personal Exchange account (personal@mainmail.com) -> recipient sees sender as personal@mainmail.com (=OK)
* User creates mail while in the main account, but changes the 'from' to the personal Exchange account (personal@mainmail.com) -> recipient sees sender as personal@mainmail.com (=OK)
* user sends mail from the main account (mail@mail1.com) -> recipient sees sender as mail@mail1.com (=OK)
* user creates new mail while in the main account, but changes the 'from' to mail@mail2.com -> recipient sees sender as mail@mail2.com (=OK)
But when sending a mail from an Office application (like Word/Excel -> file-> share -> email) the results are as follows:
* User creates mail while in the main account, but changes the 'from' to the personal Exchange account (personal@mainmail.com) -> recipient sees sender as personal@mainmail.com (=OK)
* user sends mail from the main account (mail@mail1.com) -> recipient sees sender as mail@mail1.com (=OK)
* user creates new mail while in the main account, but changes the 'from' to mail@mail2.com -> recipient seessender as the main account mail@mail1.com but 'send on behalf' as the mail@mail2.com (=ERROR)
The latter should never ever happen, because the maildomains (in my organization) should be completly seperated from each other
Why is MS doing this? And is it possible to avoid this?