GroupWise user is performing a Free Busy request for an Office 365 user. You are seeing the below error in ExchangeFreeBusyService.wlog:
2014-10-16 18:43:00,744 [3] ERROR AutodiscoverWorker - System.Net.WebException: The remote server returned an error: (457) https://autodiscover-s.outlook.com/owa/tenantdomain.onmicrosoft.com.
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.Exchange.WebServices.Data.EwsHttpWebRequest.Microsoft.Exchange.WebServices.Data.IEwsHttpWebRequest.GetResponse()
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetLegacyUserSettingsAtUrl[TSettings](String emailAddress, Uri url)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetLegacyUserSettings[TSettings](String emailAddress)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetLegacyUserSettings(String emailAddress, List`1 requestedSettings)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetUserSettings(String userSmtpAddress, UserSettingName[] userSettingNames)
at Quest.CMX.API.Core.FreeBusyExchange.AutodiscoverWorker.AttemptRetrievalOfEwsUrl()
2014-10-16 18:43:00,759 [3] INFO AutodiscoverWorker - Response is null
2014-10-16 18:43:07,811 [3] ERROR AutodiscoverWorker - System.Net.WebException: The remote server returned an error: (457) https://autodiscover-s.outlook.com/owa/tenantdomain.onmicrosoft.com.
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.Exchange.WebServices.Data.EwsHttpWebRequest.Microsoft.Exchange.WebServices.Data.IEwsHttpWebRequest.GetResponse()
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetLegacyUserSettingsAtUrl[TSettings](String emailAddress, Uri url)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetLegacyUserSettings[TSettings](String emailAddress)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetLegacyUserSettings(String emailAddress, List`1 requestedSettings)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetUserSettings(String userSmtpAddress, UserSettingName[] userSettingNames)
at Quest.CMX.API.Core.FreeBusyExchange.AutodiscoverWorker.AttemptRetrievalOfEwsUrl()
2014-10-16 18:43:07,811 [3] INFO AutodiscoverWorker - Response is null
2014-10-16 18:43:07,811 [3] WARN AutodiscoverWorker - Could not autodiscover EWS URI.
2014-10-16 18:43:07,811 [3] INFO AutodiscoverWorker - 00:00:13.7879145
2014-10-16 18:43:07,811 [3] WARN ExchangeFreeBusyConnector - Unable to determine EWS URI for user groupwise.migration@domain.com.
2014-10-16 18:43:07,826 [3] INFO ExchangeFreeBusyConnector - GetFreeBusyInfo() End 00:00:13.8052280
2014-10-16 18:43:07,826 [3] INFO FreeBusyWcfServiceBase - GetFreeBusyForUsers() End Elapsed Time 00:00:13.8355143
