Send on Behalf not working in specific situation

New Contributor

We've a hybrid exchange 2013 and Exchange online environment where all mailboxes are migrated to the cloud. I've set Send-On-Behalf permissions correctly but it doesn't work if you add the profile in Outlook in a specific way.


send-on-behalf works:

In Outlook365 go to File>Account Settings>Account Settings>select your email address>change>more settings>tab advanced> add the mailbox with the send-on-behalf permission


send-on-behalf does not work:

In Outlook365 go to File>Info>Add Account>follow the wizard


Is it not possible to send-on-behalf in the second situation?


We've chozen for the second option because we've a lot of shared mailboxes, if you add them to your profile a seperate ost file is created instead it is added to your own ost file which could cause performance issues on growth.


Regards Remco

5 Replies



Thnx for your reply. I've tested the automapping, which works, however automapping is adding the shared mailbox to your own profile (pst) instead of creating a seperat pst file.

best response confirmed by Remco_Tiel (New Contributor)

In the second scenario, Outlook is effectively using Send As permissions, so just add those and be done with it :) If you insist on using Send on behalf of, you need to make sure to always select the "send using" dropdown, as detailed in the article linked above.

@Vasil Michev 


thnx for the your answer. it is what it is so I'm done with it ;) and will only use send-as.