SBS 2011 Exchange - Outlook clients intermittently asking for credentials

Question

I have an SBS 2011 Standard machine that clients running Microsoft Outlook 2007 and 2010 have issues connecting to - every hour or so they are asked to enter mailbox account credentials.

The server is as follows:

• Fully patched with Windows Updates
• After out-of-box install, the Autodiscover record was missing in the DNS (this was added - still same issue)
• Self signed certificate is being used not a purchased UC subject-alternate-name cert
• User ticks Remember Password in Outlook, but it still pops up again later anyway
• User clicks cancel without entering details, and they can still send/receive!
• Clients and server are all on the same subnet
• No antivirus or firewall is in place that would block any traffic
• iPhones installed with the self signed cert work with active sync perfectly fine

Can someone kindly advise:

1. What the issue may be and how to diagnose further?
2. If Subject-Alternate-Name certificates are required for SBS or if self-signed is OK
3. Most importantly, how to enable tracing in Outlook or SBS so I can find out why credentials are being asked

Answer 1

One thing that could be worth checking is if the Exchange Address Book service is running, as it tends to start a bit early with the latest patches for Exchange, and then fail starting up.

Answer 2

Several things to validate:

1. Make sure dcdiag comes back clean. Resolve any issues if found.
2. Make sure IP of the SBS server is correctly configured on client's machines and is the only DNS.
3. Double-check correct configuration of the DNS on the server.

Couple things to note:

You don't need AUTODISCOVER config on the internal network. Internal Exchange cert is enough, given it's correctly imported/trusted by the clients. SAN is not required on the internal network.

Answer 3

Few things to check:

1. Do you have only one DNS set on clients (SBS DNS) or do you use additional DNS as a failsafe? If the 2nd remove the 2nd dns.

2. Right click on Outlook icon holding CTRL and make sure Show Microsoft Exchange Messages , Show Network Warnings, Show Network Connectivity changes are checked.

3. Any errors/warnings in Application Log, Service log on your SBS machine?

4. Is SBS license activated and within scope? In SBS 2003 when limit of users corresponding to license was reached SBS freaks out. Maybe it's a case here as well. Check logs thou on both SBS and local machine. It will tell you the truth.

5. User ticks Remember Password in Outlook, but it still pops up again later anyway does often require additional steps to work properly. You may need to add domains into Local Intranet settings in Internet Explorer (you can do it thru GPO). Add something like *.yourdomain.com, *.yourdomain.local. Otherwise the password isn't always remembered correctly.

6. Make sure all Exchange services are running.

Answer 4

One of our tech team found this. Check for the Microsoft update KB2596598 on the PC. If it is there uninstall it. It seems to be this update affecting PCs running Windows XP and Office 2007 on Exchange 2010.