When one of my users (only one of them) is sending an email the from address shows 'From: /o=DOMAIN/ou=first administrative group/cn=Recipients/cn=Login_name On Behalf Of User_name'
After investigating a bit, it seems to be related to the LegacyExchangeDN.
When I compare the settings for this user vs. the others, it looks like he is the only one that the x.400 address is at the top of his email addresses (in exchange mailbox settings). For all other users x.400 address (containing the above mentioned string) is the last one.
How can I either remove it or move it to the end of the list like all others?