Where's my display name?!

Hey everyone, 

I just set up my entire team with an Outlook account. Each person has their own display name (First, Last) and other personal information attached via the 'Identity' tab in the admin center. 

My issue is that when a team member sends an email it arrives the in the recipients inbox as 'email address removed for privacy reasons' instead of the display name of 'Joe Montana.' 

How and what do I change to ensure the recipient of the email sees the name of the sender rather than their whole email address. It's affecting our deliverability because it looks spammy. 

Any help would be appreciated!