Hi Experts,

Here are the HW & SW.

DC1, ADC Windows 2012

Exchange 2013 MBX1 & MBX2 on Win2012r2

Exchange 2013 CAS1 & CAS2 on Win2012r2

Network : EXCHANGE ON LAN and Clients using MPLS link to connect Exchange CAS (10 mbps) 100 users.

Strange issue, only for few users like 4-5 outlook, when user opens outlook gets authenticated and outlook remain cached mode. But it doesn't gets the new mails it still shows online. But the same users they get the mails on their mobile device using Active Sync promptly without any delay and new mails shows on the OWA too. When the user restarts his outlook starts receiving new emails. 

Checked the following : 

No Application error on event logs

All users are homed on same database on same server.

No throttling policy been configured and enabled except default one.

Webmail works fine and well

Restarting outlook syncs well

No network changes

Both internal and external mails are affected for the few users who has issues

Hi,

Since there is no sync synchronization issue on mobile device and OWA, it is highly possible of outlook client issue.

• Make sure outlook client is the latest version.

• Please disable the security AVG/Firewall, especially the mail scanner module to check whether this issue persists.
• Run Outlook in Safe Mode to determine if it's 3rd-party add-ins related:

Press Win + R and type outlook.exe /safe in the blank box, then press Enter.

• Please run scanost.exe to fix the .pst file to test the result:

http://support.microsoft.com/kb/272227#appliesto

• Please try to recreate profile to check this issue.

If this issue persists, please let me know.

Best Regards.

• Edited by Lynn-Li 3 hours 31 minutes ago

Hi,

Since there is no sync synchronization issue on mobile device and OWA, it is highly possible of outlook client issue.

• Make sure outlook client is the latest version.

• Please disable the security AVG/Firewall, especially the mail scanner module to check whether this issue persists.
• Run Outlook in Safe Mode to determine if it's 3rd-party add-ins related:

Press Win + R and type outlook.exe /safe in the blank box, then press Enter.

• Please run scanost.exe to fix the .pst file to test the result:

http://support.microsoft.com/kb/272227#appliesto

• Please try to recreate profile to check this issue.

If this issue persists, please let me know.

Best Regards.

• Edited by Lynn-Li Monday, February 16, 2015 8:17 AM

Hi Lynn-Li,

Here are our test

Outlook 2013 version used for all users.

Disabled antivirus for testing.

Outlook /safe didn't help

Tried recreating profile

SCANOST doesn't seems relevant, the profile is already recreated and same issue.

Anything to check on Exchange 2013 CAS and MBX server?