EDIT 9/19/2023: This blog post has received significant update.
In this second part of the Demystifying Hybrid Free/Busy, we will cover troubleshooting of Hybrid Free/Busy scenarios, more specifica...
Updated Sep 19, 2023
Version 16.0
Blog Post
I didnt see this error on your list. The issue we are having is an O365 user can not see the free/busy calendar for an Exchange 2010 user. The Exchange user can see the Free/Busy of the O365 user. When this issue happened in the past, I would run IISREST on the Exchange 2010 CAS servers and the problem would be fixed. This time, its not working. Any ideas?
Performing Free/Busy LookupFree/Busy Lookup failed.
Additional Details
Free/Busy Lookup failed with exception: Proxy web request failed. , inner exception: System.Web.Services.Protocols.SoapHeaderException: An error occurred when processing the security tokens in the message. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.EndInvoke(IAsyncResult asyncResult) at Microsoft.Exchange.InfoWorker.Common.Availability.Proxy.Service.EndGetUserAvailability(IAsyncResult asyncResult) at Microsoft.Exchange.InfoWorker.Common.Availability.FreeBusyApplication.EndProxyWebRequest(ProxyWebRequest proxyWebRequest, QueryList queryList, IService service, IAsyncResult asyncResult) at Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequest.EndInvoke(IAsyncResult asyncResult) at Microsoft.Exchange.InfoWorker.Common.Availability.AsyncWebRequest.EndInvokeWithErrorHandling()