How do I add users to Crossware Mail Service in Office 365?
Adding users to Crossware Mail Signature can be done easily through your Office 365 environment by adding users to the Group created during your initial Crossware Mail Signature setup (CrosswareMailSignatureUsers).
Any user within this Group will have their emails passed to the Crossware Servers for signature processing.
1. Go to "Office 365 Admin Center" > "Admin" > "Exchange" > "Recipients" > "Groups".
2. Find the "CrosswareMailSignatureUsers" group.
3. Add users or groups.
When a new user is added to an Office 365 group, it can take up to 15 minutes before this group is updated and this user is made available for the Crossware Mail Signature service.
If after 15 minutes the signature is still not being affixed, you can check whether the user is available in this group by using Graph Explorer