Outlook 2010/Exchange 2010 Multi Mailboxes (Server unavailable)

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Outlook version
Outlook 2010 32 bit
Email Account
Exchange Server
RE: Outlook 2010/Exchange 2010 Multi Mailboxes (Server unavailable)


We have a couple of users (So Far) using multiple mailboxes, which are set up in Outlook 2010 by adding the mailboxes via Control Panel/Mail etc (Because they need to send mail from these mailboxes)

Some times when they try to send an item as attachement (Excel or PDF) they get the "server unavailable" error.

If you select "Offline" another server unavailable" error appears.

This seeme to happen for every attached mailbox (i.e. if user has 5 mailboxes, it will server unavailable 5 times, )

It almost seems as if it checks through the additional 5 mailboxes first and displays "server unavailable, until it gets to the Primary mailbox.

It will then work OK, until user logs out and back in again.

Any Ideas??

Are you caching the mailboxes?

Any events in the Event viewer?

Is the user using multiple computers or smartphone to access the mailbox?

I'm thinking there is a throttling policy and the user's account has too many connections open. you can check for a open connections using Get-LogonStatistics cmdlet:

Get-LogonStatistics <UserID> | Fl ApplicationId

No, we are not caching these mailboxes, and No, I cant see anything in the Event logs on the users machine or the server.

I created a test user with the same attributes and mailboxes. and this is the result when trying to send a document (Excel or PDF) with 6 additional mailboxes added. The users mailbox stacey.test is set as the primary mailbox to send from.

This is the result of the suggested command line query. (Attached)

You think it could be a MAPI error? i.e. running out of MAPI connections?

That is interesting, because we have introduced another NEW Exchange Server recently (Not live yet) with a view to migrating our Live Mailboxes over to it in the future.

Can I increase available connections on Exchange 2010?



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Yeah, i do think its a mapi error - and yes, you should be able to increase it just for this one user. I don't recommend increasing it for all users as it can affect the server resources.
Thanks for the reply,

Hope I don't sound stupid!

How do you increase the MAPI connections for this user mailbox?

I assume it is getting errors because they are adding up to 6 more mailboxes into thier outlook.
Not stupid at all. :) I have to look it up...

Understanding Client Throttling Policies: Exchange 2010 Help

Managing Performance with Client Throttling Policies: Exchange 2010 Help

Set-ThrottlingPolicy: Exchange 2010 Help

To raise it for everyone:

Set-ThrottlingPolicy -EWSMaxConcurrency 10

Create a new policy for a few users:

New-ThrottlingPolicy <NewPolicyName> -EWSMaxConcurrency 10

apply the policy to a user or to a group - adding the users to a group and apply the policy to the group is usually recommended

Set-ThrottlingPolicyAssociation -Identity alias -ThrottlingPolicy <Throttling Policy Name>
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