Hi fellow IT Professionals,

Were running an Exchange 2013 / Office 365 hybrid, with federation services.

All the our email-enabled user accounts are in O365, while service accounts are on-prem. We have 4 DC's (2012), singe domain, and two recently (<6 months) upgraded Exchange 2013 servers - although the issues we've been experiencing come long before any upgrade.

We have a strange error where about half the company, can't get their Lync 2013 (and now Skype for Business) working properly. while the rest have no errors.

Since everything is O365, and we've never had an on-prem Lync/UCS server, I don't know why Skype is still moaning about UCS.

I have read endless threads and blogs on the problem, and we are yet to get a working solution.

This does however seems to be more common than what I originally thought.

We've done the following, among many, and are yet to get a permanent solution:

1. Deleting sign-in information/re-signing in.
2. Doing all manner of funny things here --> %AppData%\Roaming\Microsoft\Office\15.0\Lync
3. ..even fiddling here: HKLM/HKCU/Software/Microsoft/Office/15.0/Lync - be it adding, removing or modifying keys.
4. Checked and re-checked on prem DNS, and outside DNS.
5. Double check O365 settings (both client and admin)
6. Completely removing Office, and then re-installing + repairing.
7. Deleting and recreating account 
8. Phoning Microsoft - Veryunhelpful.
9. Running Process Monitory to see what lync.exe is doing.
10. Checked Firewall and ports.

Observations:

• Majority of the users experiencing the issue, came from pre Exchange 2013/Lync 2013/Skype for business upgrade. Newly created users do no seem to have the problem (unconfirmed).
• Downloading Office Pro Plus from the web, and then immediately signing in with a known problem user account, causes the error immediately. Signing out then signing in with a user account known to work, does NOT product the problem - So I doubt it's software.
• The fact that some users are connecting fine, indicates that the problem is not DNS related.
• Going over the AD accounts line by line does not reveal any differences between a working and non working account.
• OS does not play a role in the error. Both Windows 7, and 8.1 users are experiencing the issue.
• It's not a firewall related issue because - some connect users connect fine.

Bottom exclamation mark:

The Exchange server isn't letting us connect. Please try signing out and back in. Your Outlook contact and calendar info won't be available until the connection is fixed"

When trying to add a contact/group:

"Cannot add, remove, or move contacts or groups at this time. Please try again later"

Connectivity and DNS test:

All A.O.K

http://postimg.org/image/6p8b48yhd/

1. Here is the configuration information from SfB/Lync2k13:

http://s3.postimg.org/a8ohsop75/screenshot_12.png

Text version differences:

Working Skype:

Contact List Provider;Skype for Business Server;--;

MAPI Information;MAPI Status OK;MAPI Status OK;

Container list Preferred Endpoint;TRUE;--;

Non-working Skype:

 Contact List Provider;UCS;--;

MAPI Information;Your Outlook profile is not configured correctly. Contact your support team with this information.;MAPI unavailable;

Container list Preferred Endpoint;FALSE;--;

More on this post: https://social.technet.microsoft.com/Forums/office/en-US/4ca90df9-1758-4c87-b251-2a38939054a8/skype-for-businesslync-2013-skype-for-business-cant-conect-to-exchange-cannot-addremove-or?forum=lyncprofile