EWS .NET API: Invalid named property error when setting an extended property to EmailMessage object RRS feed

  • Question

  • Hi,

    I am using EWS .NET API.

    When I try to set extended property using either default property set or my custom GUID as property set Id in the .NET code, I receive error 'An internal server error occurred. The operation failed., Invalid named property: [{1ea5aebe-567f-44c7-8b26-936bf90ea5fd}:'PropertyName'] GuidName_PropertyName'.

    The mail box is on Office 365.

    This error is occurring to a specific mail box. The code works well for other mail boxes.

    With regards,


    Wednesday, January 11, 2017 11:18 AM

All replies

  • Hello,

    Witch method used for configuring mailboxes ? Impersonation or a dedicated user account ?

    If the code works fine on any other mailbox, I suggest checking permissions on this particular mailbox, litigation hold ...


    Friday, January 13, 2017 3:03 PM
  • Hi, I am in a similar problem. Did you get the issue resolved?


    Yahtasham Reezvi

    Friday, August 3, 2018 10:16 AM