Configuring Sent Items Behavior in Exchange 2016

• Saving Sent Items can be on Shared Mailboxes Only (Converting Mailbox to Shared to Set-Mailbox MailboxName –Type Shared)

Get-Mailbox test2016-4 | Set-Mailbox -MessageCopyForSendOnBehalfEnabled:$true -MessageCopyForSentAsEnabled:$true

User1 do SendAs on Test2016-4 Mailbox

Now in Test2016-4  Sent Items you can see Items being saved. Which is not by default.

Enabling From in Outlook Web Access After Applying SendAs Permission in Shared mailbox delegation properties.

From –

Send As is Saved to SharedMailbox