I am trying to add contacts to my users' contacts folders via the EWS Managed API but when I try to add a significant number of contacts (usually over a hundred or so) to a user's folder I often come across the following error:
Microsoft.Exchange.WebServices.Data.ServiceResponseException: The operation can't be performed because the item is out of date. Reload the item and try again.
When I re-run the process it seems to move on a few contacts and then fails again but if I leave it for a while or run it out of office hours it seems to work which makes me think that some other process is interrupting it.
Has anyone else come across this error and found a solution to it?