Exchange 2013: Outlook Anywhere periodicaly disconnects and reconnects

Question

For some reason when external use Outlook Anywhere, after a while it disconnects from the Exchange server and tries to connect, then in few minutes it successfully connects again. All this time all the Exchange servers stays untouched.

Many of our users are experiencing this issue.

Tested the scenario with different versions of outlook, 2010, 2013, 2016. all of them experience the disconnects. I have tested at various locations with wired ethernet connection and WiFi. At all the locations the issue persists. Exchange cached mode is off

I haven't spotted any relevant events in the eventviewer on the Exchange and TMG servers.

Our environment consists of a number of exchange servers, we use MAPI over HTTP connections to connect to the mailboxes. Autodiscover is configured. We make use of a TMG firewall server.

All of the Exchange servers run Windows Server 2012 R2, the TMG server runs on Windows Server 2008R2.

here are the various Exchange servers, and their roles:

ServerRole          : Mailbox, ClientAccess
Edition             : Enterprise
AdminDisplayVersion : Version 15.0 (Build 1076.9)

ServerRole          : Mailbox, ClientAccess
Edition             : Enterprise
AdminDisplayVersion : Version 15.0 (Build 1076.9)

ServerRole          : ClientAccess
Edition             : Enterprise
AdminDisplayVersion : Version 15.0 (Build 1076.9)

ServerRole          : Mailbox, ClientAccess
Edition             : Enterprise
AdminDisplayVersion : Version 15.0 (Build 1076.9)

this are the Exchang MAPI and Outlook Anywhere virtual directories and their URL's:

        MAPI:
        InternalUrl                    ExternalUrl
        -----------                    -----------
        https://mail.domain.com/mapi https://mail.domain.com/mapi
        https://mail.domain.com/mapi https://mail.domain.com/mapi
        https://mail.domain.com/mapi https://mail.domain.com/mapi
        https://mail.domain.com/mapi https://mail.domain.com/mapi


        Outlook Anywhere:

        ExternalHostname  InternalHostname
        ----------------  ----------------
        mail.domain.com casserver.domain.com
        mail.domain.com casserver.domain.com
        mail.domain.com casserver.domain.com

All of the Exchange servers are on Exchange Server 2013 CU8.

When the connection drops, this is what the TMG server shows in it's filter:

How can I resolve this issue?

Are multiple users experiencing the same problem or is it just one user? If the latter, it could be a problem at the client end. — Todd Wilcox, Feb 26 '16 at 14:22
The error message stipulate that it's the remote host that closed the connection, as such I would like to know what outlook the client got, what OS version, AV, any error in the event log, does they connect via a vpn, etc.. — yagmoth555, Feb 26 '16 at 14:40
Can you tell if all the users are getting disconnected at the same time or is it different times for each user? Also, are all the client computers in the same place or are they in various remote locations? Are the clients configured to use cached Exchange mode? — Todd Wilcox, Feb 26 '16 at 14:42
@yagmoth555 Updated my question, Todd Wilcox, I will check if the time differs when using multiple machines. Cached exchange mode is off. — doenoe, Feb 26 '16 at 14:48
Exchange to the lastest CU and the remote outlook ? & do you see any eventlog error in the remote machine ? — yagmoth555, Feb 26 '16 at 14:57
My guess is that the TMG is dropping idle connections and causing this issue. Have a read here: http://blogs.iis.net/windowsserver/sent-items-delayed-when-publishing-outlook-anywhere-through-tmg — joeqwerty, Feb 26 '16 at 15:10
@joeqwerty Adjusted the KeepAlive settings as mentioned in your commect, rebooted the boxes, does not seem the make any difference. Still getting connection drops — doenoe, Apr 01 '16 at 11:59

score 0 · Answer 1 · answered Feb 26 '16 at 15:01

0

Have the user open the Microsft Exchange Proxy Settings within their outlook, uncheck "On fast networks, connect using HTTP first, then connect using TCP/IP" and check "On slow networks, connect using HTTP first, then connect using TCP/IP"

Exchange 2010 Outlook Anywhere Connection Randomly Drops Out
"To ensure that Outlook clients retain their connection with the Exchange server using HTTP and not TCP both "On fast networks, conect using HTTP first" and "On slow networks, connect using HTTP first" must be selected."

If this resolves it, you might want to implement this on a wider scale

answered Feb 26 '16 at 15:01

Lex

574
2
6
16

For some reason i dont have the `connection` tab in my `Outlook 2016` client.. Only `General`, `Advanced` and `Security`. – doenoe Feb 26 '16 at 15:07
@doenoe That tab was removed in, I believe, Outlook 2013. Everything has to be configured through Autodiscover now. – Michael Steele May 10 '17 at 16:37

score 0 · Accepted Answer · answered Apr 07 '16 at 09:19

CU11 contains the following fix:

https://support.microsoft.com/en-us/kb/3099522

https://support.microsoft.com/en-us/kb/3105690

FIX: Outlook clients that use MAPI over HTTP to connect to Microsoft Exchange Server 2013 mailboxes are intermittently disconnected

Upgraded to CU12, no disconnects have occured since.

Exchange 2013: Outlook Anywhere periodicaly disconnects and reconnects

2 Answers2