Monitor just caught this exception getting thrown by the server:

System.Runtime.Serialization.SerializationException: The data contract type 'Microsoft.Exchange.Services.Core.Types.ItemId' cannot be deserialized because the required data member 'Id' was not found along with a large exception stack trace.

It occurred in <AppDomain>/LM/W3SVC/2/ROOT/owa-3-130752569863010601</AppDomain> at System.Runtime.Serialization.Json.XmlObjectSerializerReadContextComplexJson.ThrowMissingRequiredMembers(Object obj, XmlDictionaryString[] memberNames, Byte[] expectedElements, Byte[] requiredElements)

I can't find any articles online as to where I should begin to address this.  It's the first time this has popped since this machine went live.

Hi,

Its hard to find the root cause according to this error.

Are there any impacts on OWA or client?

Have you ever done some customization on IIS? Especially in OWA. Or what had been configured recently?

Similar thread:

https://social.technet.microsoft.com/Forums/office/en-US/2245f608-c169-45e2-abb1-07f3d1570c5f/eventid-65535?forum=exchangesvrgeneral

Best Re

Now that you mention it - the login.aspx page was modified to change the text "Email Address" to "Compliant Email Address" so the handlebar tag was removed and placed with static text.

Could this exception be that?  Hence, the {ID} missing?