Hi , we have a customer that fo some particular reason have 17 device ( PC ) who need to have outlook configured on the same exchange account ( I know we tried to talk him out of it but to no avail ) , the problem we are facing is that only the first Computer can connect succesfully and then the remeaing device are unable to connect to Exchange ( disconnected from exchange ) . Basically is a first came first serve. I have already created a Throttling policy for these users and set RCAMaxConcurrent to Unlimited but even this did not solve my issue. I am sure I am hitting some limit imposed from the exchange server but have no clue which one

Thanks

Hi ,

Please check this link it may help you.

https://social.technet.microsoft.com/Forums/office/en-US/b303e2a8-d650-47e1-9a1f-13f7d06d3e0b/single-mailbox-opened-in-multipul-outlook-clients?forum=exchangesvrgeneral

Hi , and thanks for the answer , I already created a throttling policy to no avail , to give more info I just extrated this from the RPC log for the selected user :

<user identity>. -> [MapiExceptionSessionLimit] Unable to open message store.

Hi ,

Please check the below mentioned blog .

http://www.msexchange.org/blogs/walther/news/so-you-still-have-issues-opening-many-shared-exchange-2010-calendars-using-outlook-2003-569.html

For a checking purpose and  to override the default store limit ,just add the below mentioned regitry keys and check the results .

• Maximum Allowed Sessions Per User

• Maximum Allowed Service Sessions Per User

Note : Before making any changes on the registry, please take a backup of full registry and also the exchange server server full backup needs to be taken in advance for a safety purpose.

Hi ,

Thank you for your question.

we could create a new throttling policy to apply this specific mailbox:

New-ThrottlingPolicy name <Name>

Set-ThrottlingPolicy identity <Name> RCAMaxConcurrency <Value>

Set-Mailbox Identity Username ThrottlingPolicy <Name>  

Notice: The RcaMaxConcurrency parameter specifies how many concurrent connections an RPC Client Access user can have against a server running Exchange 2013 at one time. A connection is held from the moment a request is received until the connection is closed or the connection is otherwise disconnected (for example, if the user goes offline). If users attempt to make more concurrent requests than their policy allows, the new connection attempt fails. However, the existing connections remain valid. The RcaMaxConcurrency parameter has a valid range from 0 through 2147483647 inclusive. The default value is 20. To indicate that the number of concurrent connections should be unthrottled (no limit), this value should be set to $null.

We could refer to the following link:

https://technet.microsoft.com/en-us/library/dd298094(v=exchg.150).aspx

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim