The setting SupportedIPMTypes in the Web.Config file was missing. Using default value of System.Collections.Generic.List`1[System.String].

Hello,

There are several closed topics on technet specifying this ActiveSync eventlog issue after a clean Exchange 2013 / Exchange 2016 deployment. The application eventlog is displaying the warnings "The setting SupportedIPMTypes in the Web.Config file was missing.  Using default value of System.Collections.Generic.List`1[System.String]." and "The setting LiveIdBasicAuthModule.ApplicationName in the Web.Config file was missing.  Using default value of .".

Reference posts which are closed without a proper solution:

https://social.technet.microsoft.com/Forums/en-US/dff62411-fad8-4d0c-9bdb-037374644845/event-1033-msexchangeactivesync-warning?forum=exchangesvrmobility

https://social.technet.microsoft.com/Forums/ie/en-US/310c19c9-a0b7-40f3-96ab-ff1644b5e824/exchange-2016-event-id-1033-the-setting-supportedipmtypes-in-the-webconfig-file-was-missing?forum=Exch2016GD

https://qa.social.technet.microsoft.com/Forums/en-US/dff62411-fad8-4d0c-9bdb-037374644845/event-1033-msexchangeactivesync-warning?forum=exchangesvrmobility

A solution was posted for the error LiveIdBasicAuthModule.ApplicationName , however not for the error "SupportedIPMTypes".

The solution is as follows:

1. Edit the \Program Files\Microsoft\Exchange Server\V15\ClientAccess\Sync\Web.config file and add the following lines under <appSettings>:

    <add key="SupportedIPMTypes" value="IPM.Activity","IPM.Appointment","IPM.Contact","IPM.DistList","IPM.Document","IPM.OLE.Class","IPM","IPM.Note","IPM.Note.IMC.Notification","IPM.Note.Rules.OofTemplate.Microsoft","IPM.Post","IPM.StickyNote","IPM.Recall.Report","IPM.Outlook.Recall","IPM.Remote","IPM.Note.Rules.ReplyTemplate.Microsoft","IPM.Report","IPM.Resend","IPM.Schedule.Meeting.Canceled","IPM.Schedule.Meeting.Request","IPM.Schedule.Meeting.Resp.Neg","IPM.Schedule.Meeting.Resp.Pos","IPM.Schedule.Meeting.Resp.Tent","IPM.Note.Secure","IPM.Note.Secure.Sign","IPM.Task","IPM.TaskRequest.Accept","IPM.TaskRequest.Decline","IPM.TaskRequest","IPM.TaskRequest.Update"></add>
    <add key="LiveIdBasicAuthModule.ApplicationName" value=""></add>

2. IISReset, and the events are not written to the eventlog anymore.

For all IPM types see:

https://docs.microsoft.com/en-us/office/vba/outlook/concepts/forms/item-types-and-message-classes

3. Beware that with every cumulative update, the web.config files could be overwritten so you would have to add it again.