We have some remote sites connected by IPSEC site-to-site VPN. Users run Outlook 2007 connected to Exchange 2007 at the main site.

It is common for Outlook to go through periods of  losing and regaining connections: Outlook displays constantly connection messages. The error occurs on an intermittent basis and does not effect all users at the remote site, the problem usually disappears after a day. Users can get access to e-mails through OWA and this does not have the same outage errors.

Not sure if it is related to other traffic running over VPN link but I cannot find any obvious cause.

• Edited by Graham M T Tuesday, February 17, 2015 7:29 PM

Hi,

The intermittent Outlook connection issue can be caused by the following factors:

1. Network issue.

2. Exchange Server performance issue.

3. Outlook client side issues.

Whats your Exchange environment? How many Exchange servers and Server Roles?

In Exchange 2007, Outlook directly connect to Mailbox Server. So, if you have multiple Mailbox Servers, please confirm whether the problematic users are all on the same Mailbox Server. You can take a performance monitor to check whether the RPC request is too high:

http://blogs.technet.com/b/mikelag/archive/2008/05/02/perfwiz-replacement-for-exchange-2007.aspx

Thanks,