We had an end user who politely insisted that we get his Conversation History working. He was extremely patient and very helpful in our long, long period of troubleshooting. But he was persistent and kept pushing us to find a solution. I kept coming back to the thought that Exchange Web Services (EWS) weren’t working for him. Our Exchange Admin correctly pointed out that if EWS wasn’t working for him then pretty much all of Outlook wouldn’t be working for him.
As time passed and we got more desperate. I had him try to connect with this (pointless?) little utility from Microsoft – the Lync Conversation Analyzer. What value this utility actually provides is anyone’s guess but to use it you have to log in directly against EWS. I was able to connect successfully. However our troubled end user could not. Finally some proof that EWS was rejecting his connections.
We ended up opening a case with Microsoft and, to summarize, the issue is that our user had so many folders and nested folders that it hit a maximum set in the “EWSFindCountLimit” setting. So we created a new mailbox policy with an unlimited value for this setting, applied it to his mailbox and presto! Conversation History was working.
- Collect the .etl log while reproducing the issue.
- Parse the logs and find this error:
[oc]<O_TRC><ADR>0x09F38B60</ADR>Found error in CEwsMailboxFolderManagerTask response.
[oc]<O_TRC><ADR>0x09F38B60</ADR>CEwsMailboxFolderManagerTask response code changed.
- This error could be caused by the Throttling policy in Exchange Server 2010.
- We can run the command to disabled the“EWSFindCountLimit”
Get-ThrottlingPolicy “Default*”| Set-ThrottlingPolicy -EWSFindCountLimit $null
- Created a new throttling policy using the below command,
New-ThrottlingPolicy -Name Test
- Then set EWSFindCountLimit to Null using
Set-ThrottlingPolicy -Identity Test -EWSFindCountLimit $null
- Then assigned the policy to the user mailbox using
Set-Mailbox -Identity <UserName> -ThrottlingPolicy Test