Meeting organizer receives multiple responses from an attendee

Applies to: Exchange OnlineExchange Server 2016 Enterprise EditionExchange Server 2016 Standard Edition


The organizer of a meeting receives multiple meeting responses from an attendee. An analysis of the IIS logs shows multiple MeetingResponse commands from the user's device. These commands resemble the following:
2015-11-18 13:48:57 POST /Microsoft-Server-ActiveSync/Proxy/default.eas


This issue occurs because the attendee responded to an instance of a recurring meeting by using an iOS 9.x device. The device does not correctly parse the response from the server that is running Exchange Server. Therefore, the server continues to send the meeting response.


To resolve this issue, apply the iOS 9.3 update. Apple has documented the issue in the following article in the Apple Knowledge Base:

Note The referenced article mentions the fix for this issue in bullet item 6 in the "Enterprise bug fixes" section for iOS 9.3.

More information

You can use the following Log Parser Studio query to identify users who are affected by this issue:
/* Query to find MeetingResponse commands by user device */SELECT COUNT(*) As Hits,EXTRACT_VALUE(cs-uri-query,'DeviceType') AS DeviceType,EXTRACT_VALUE(cs-uri-query,'DeviceId') AS DeviceId,REPLACE_STR(TO_STRING(EXTRACT_PREFIX(EXTRACT_SUFFIX(cs-uri-query, 0, '_SmtpAdrs:'), 0, '_')), '%40', '@') As User,EXTRACT_VALUE(cs-uri-query,'Cmd') AS CmdFROM '[LOGFILEPATH]' WHERE cs-uri-stem LIKE '%Active%' AND Cmd LIKE '%MeetingResponse%'GROUP BY DeviceType,DeviceId,Cmd,UserORDER BY Hits DESC