Demystifying Hybrid Free/Busy: Finding errors and troubleshooting

Hi Mirela_Buru

We have an issue with not seeing free/busy from only online exchange to on-prem exchange (works in the other direction fine) I have reviewed you post (great) and have a getuseravailabiltyinternal that is kind of like #3 from your list but not quite. We suspect that something on our cloud configuration is not correct. Do you have any thoughts? 

{"Header":{"ServerVersionInfo":{"MajorVersion":15,"MinorVersion":20,"MajorBuildNumber":3433,"MinorBuildNumber":45,"Version":"V2018_01_08"}},"Body":{"Responses":[{"ResponseMessage":{"__type":"SingleResponseMessage:#Exchange","MessageText":"Proxy web request failed. , inner exception: System.Web.Services.Protocols.SoapHeaderException: An error occurred when verifying security for the message.\r\n at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)\r\n at System.Web.Services.Protocols.SoapHttpClientProtocol.EndInvoke(IAsyncResult asyncResult)\r\n at Microsoft.Exchange.InfoWorker.Common.Availability.Proxy.Service.EndGetUserAvailability(IAsyncResult asyncResult)\r\n at Microsoft.Exchange.InfoWorker.Common.Availability.FreeBusyApplication.EndProxyWebRequest(ProxyWebRequest proxyWebRequest, QueryList queryList, IService service, IAsyncResult asyncResult)\r\n at Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequest.EndInvoke(IAsyncResult asyncResult)\r\n at Microsoft.Exchange.InfoWorker.Common.Availability.AsyncWebRequest.EndInvokeWithErrorHandling()","ResponseCode":"ErrorProxyRequestProcessingFailed","MessageXml":"<?xml version=\"1.0\"?>\r\n<XmlNodeArray xmlns:t=\"http://schemas.microsoft.com/exchange/services/2006/types\" xmlns:m=\"http://schemas.microsoft.com/exchange/services/2006/messages\">\r\n <ExceptionType xmlns=\"http://schemas.microsoft.com/exchange/services/2006/errors\">ProxyWebRequestProcessingException</ExceptionType>\r\n <ExceptionCode xmlns=\"http://schemas.microsoft.com/exchange/services/2006/errors\">5016</ExceptionCode>\r\n <ExceptionServerName xmlns=\"http://schemas.microsoft.com/exchange/services/2006/errors\">CH2PR19MB3832</ExceptionServerName>\r\n <ExceptionMessage xmlns=\"http://schemas.microsoft.com/exchange/services/2006/errors\">Proxy web request failed. , inner exception: An error occurred when verifying security for the message. LID: 59916</ExceptionMessage>\r\n</XmlNodeArray>","ResponseClass":"Error"},"CalendarView":{"MergedFreeBusy":null,"Items":null,"WorkingHours":null,"FreeBusyViewType":"None"}}],"ResponseCode":"NoError","ResponseClass":"Success"}}

I have also ran Get-IntraOrganizationConnector  on both on-prem and exch online and both do not show any output?

thanks!

Eric