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Issue with multiple Exchange Office 365 accounts in Outlook 2010

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I am running Office 2010 on Windows 7 and I am trying to connect to 2 Office 365 Exchange accounts within our Office 365 account (i.e. 2 different email addresses that fall under the same domain in our Office 365 account).

It seems that once Outlook connects to 1 of the accounts, the other is never able to connect.  It seems to connect to the default account first, and then the 2nd Exchange account never connects.  We previously used a different Hosted Exchange provider (before Office 365) and it worked fine, so it seems that something at Office 365 is blocking this somehow ?

This is driving me crazy, so please help if you can !

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  • Brendan,

    Thank you very much for sharing your solution.  I was having just the same issue with my clients. I had multiple Users that had two or more office 365 e-mail accounts open in Outlook 2010 with the same proxy.  Users were constantly reconnecting and had trouble sending and receiving mail

    I followed your directions and it has resolved the issue.  

    Thanks again!

  • Hi Todd,

    I just emailed you the log files.  



  • Brendan, or anyone else that had implemented Brendan's fix, I am dying to get this to work.  I've located the hosts file, but am not sure exactly where I should be entering the info you specified relative to what the host file already contains, and don't want to screw something up.  I will proceed at my own risk, but would like to know if someone would be willing to upload their hosts file as an attachment so I can see exactly where/how to add the necessary entries.  I'm assuming that if a persons host file contains any private info they can just type a dummy IP address in since I'm just looking for the format for where I should enter this info.


    Thanks in advance.

  • Attached is my hosts file.  Hope this helps.
  • Deleted comments while I do further testing.
  • Brendan Erofeev (note the subtle difference)   autodiscover.[mydomainname].com

    Then, I adjusted one of my mail accounts exchange proxy settings to connect to, and left the other as-is.

    Now, when Outlook 2010 caches the credentials for my mail accounts in windows credential manager, it can cache a seperate set of credentials for each mail account, and works perfectly.

    Brendan, following your instructions, I changed the exchange proxy settings (more settings>connection>Exchange Proxy Settings) to "" and so on for each account, but incrementing up a number at the end for each different account.  However for all of them the server address remains:


    Is that correct?  That is, the only place a change needs to be made is in the exchange proxy settings (and of course the hosts file)?

  • Hi David,

    This is correct,

    The mailbox server that holds your mail is CH1PRD0502.mailbox,, and if you change this, your exchange accounts will stop working.

    What you are changing is just the proxy addresses that are used to connect through to your mailboxes.

  • I could not get Brendan's solution to work.  After living with this issue for 3 months, I moved back to Apptix.  Problem solved, I now have reliable perfect email again.  Although MS did eventually contact me (and Todd is a champ for trying to push this issue through) I just didn't have any more time to throw at it and it's a bit amazing that it's been being reported for 3 months and still isn't fixed and only recently got taken seriously and moved to a higher level.  As far as I was concerned I could have been dealing with the issue for next year for I all know.  That wasn't why I signed up for the "enterprise plan".

    This is just one issue that affects very few users, but there are so many others*, it's been a very negative experience and wasted so much time its painful.

    1. Expiring passwords that requires executing windows shell commands to shut off.  Seriously MS, this is what you think small businesses want in a cloud offering?  Getting calls without warning from people who can't access their email?

    2. Service tickets that won't submit.  So you have an issue and you can't submit a ticket!

    3. No integration with Dynamics CRM!  Sure it's coming, but when one of then huge features of your latest CRM release is sharepoint integration and then your own cloud sharepoint offering won't work with it, come on!

    4. Spam filters that can't be shut off and a host of issues related to that.

    5. This issue which was huge.

  • David,

    I apologize you struggled with this and the other issues.  We are listening to the feedback and will continue to improve the service.  You are right that there are some feature issues like having to use powershell for some common tasks.  These are priority things for us to get addressed.  

    For this issue connecting with multiple accounts Todd has been trying to recruit those impacted to contact him so we can create a support case for further investigation.  Quite a few of us have tried to reproduce the problem and have not been able to see it yet.  As soon as we can get someone to work with us to investigate the issue my team will push forward for a solution.

    If anyone else still has a repro of this issue and is willing to help us investigate it, please contact me.  I've set my profile to accept messages.  

  • Gabriel,

    I have reproduced the problem and generated the required logs.  I have sent these to Todd, and am happy to send to you as well.  Please email me: brendan at erofeev dot net

  • Gabriel, we are seeing same issue on multiple PCs. The hosts file 'hack' has resolved, but this is not an acceptable solution, as it breaks the autodiscover, and causes additional managment overhead in managing hosts files.

    I opened a service request yesterday and also emailed Todd. The issue must be with authentication / session where both users are on same O365 proxy server, as adding a dummy proxy host as per Brendan 'hack' resolves issue.

  • I have tested multiple exchange accounts on non-Microsoft client, an iPad, and I dont see any issues with authentication with multiple exchange accounts that are using same proxy server. Could the issue be with Outlook 2010 SP1 ?

  • I think the issue lies with authentication while using Outlook Anywhere (RPC over HTTPS).  Since mobile devices use ActiveSync, they do not have the same problem.

  • Craig,

    Can you please message me the support case number for the service request you opened?  

  • Gabriel, I already did earlier today. I can email you if easier, just PM me your email address?