I hope someone can help with what I thought would be a simple issue. To give a little background, we have a hybrid environment - Exchange 2010 / Exchange 2013 / Exchange Online. At the moment, there are only test mailboxes on Exchange Online. When an email is sent out from an on-premises mailbox to an external recipient, it looks like the below showing the full email address with the domain name.
If I send an email out from an Exchange Online mailbox to an external recipient however, it only shows the display name (in this case Office365 Test) and not the full email address.
How can I set this so that on-premises mailboxes also just show the display name as Exchange Online does?
SimpleDisplayName is not enabled for any domain and is not even populated for the Exchange Online account.
Thanks in advance.