Outlook 2016 & ZeroConfigExchange

[smarties11]

Hi All,

 

Have got our first IT suite set up here with Windows 10 (1803). All working beautifully so far except for one thing! I have set up ZeroConfigExchange, and in testing this worked perfectly. However, in the real world, there are some users that this doesn't work for. When opening Outlook 2016, they are prompted for their username and password, and on entering it the credentials are rejected. Outlook then quits. It's happening to around 10% of our users, and I cannot see a pattern. It moves with them, it doesn't matter which computer they use - the problem is always there. If an unaffected user logs on to the same computer afterwards, it works fine for them. I'm thinking it must be mailbox configuration, however when comparing a working mailbox to a non-working one, I cannot see any differences. Our accounts and mailboxes are created in bulk at the same time (in the past for our older users this was done with active user manager etc, in recent years with Salamander).

 

I'm scratching my head and can't see anything online. Has anyone else come across this?

 

Thanks!

 

EDIT: Just to add that we use exactly the same method on our Windows 7 machines, which works fine for everyone!

Edited September 18, 2018 by smarties11

[smarties11]

For anyone else experiencing this issue - the users that were failing to connect have a trailing space at the end of their LegacyExchangeDN attribute in AD. Removing this enables their mailbox to be opened in Outlook 2016 successfully.

 

However, doing so means that old emails from these users cannot be replied to, and anyone picking their name from the Outlook cache will receive an NDR, as the LegacyExchangeDN is the value used for routing internal mail. From my research it looks like you can fix this by creating an X500 proxy address with the old LegacyExchangeDN value, but I've yet to test this. Also need to look at our automated user creation process (salamander) to see if spaces can be stripped out at account creation stage. It seems that the LegacyExchangeDN field can only hold a certain amount of characters, and defaults to using the display name at the end of the string. If this value ends on a space when truncated, the issue in my OP presents itself. We have (School Name - Pupil/Staff) at the end of all our display names so the chances of truncating on a space are reasonably high, running a PowerShell query shows around 80 out of our 900 of our users are affected. Thankfully only two members of staff!

 

Hope this helps someone....