Hello, on our on-prmise Skype For Business 2015 installation we see the follwing Error in the Event Log for Lync.

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Event 32054 - LS Storage Service

Storage Service had an EWS Autodiscovery failure.

StoreWebException: code=ErrorEwsAutodiscover, reason=GetUserSettings failed, smtpAddress=xxx.yyy@company.de, Autodiscover Uri=https://autodiscover.company.de/autodiscover/autodiscover.svc, Autodiscover WebProxy=<NULL>, WebExceptionStatus=ProtocolError ---> System.Net.WebException: The remote server returned an error: (405) Method Not Allowed.
   at System.Net.HttpWebRequest.GetResponse()
   at Microsoft.Exchange.WebServices.Data.EwsHttpWebRequest.Microsoft.Exchange.WebServices.Data.IEwsHttpWebRequest.GetResponse()
   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverRequest.InternalExecute()
   --- End of inner exception stack trace ---
   at Microsoft.Rtc.Internal.Storage.Exchange.ExchangeContext.SendGetUserSettingsRequest(StoreContext ctx, String smtpAddress)
   at Microsoft.Rtc.Internal.Storage.Exchange.ExchangeContext.GetUserEwsSettings(StoreContext ctx, String smtpAddress, CacheMode cacheMode)

Cause: Autodiscovery Uri was not correctly configured or unreachable, that there is a problem with the Proxy, or other errors.
Resolution:
Check event details.  Check autodiscovery Uri is properly configured and reachable. Check that proxy setting is properly configured and reachable.  Validate Skype for Business to Exchange Autodiscovery configuration by following the trouble shooting guide. If problem persists, notify your organization's support team with the event details.

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From our investigations and test made via www.testexchangeconnectivity.com we can confirm that the requested autodiscover URL is reachable. We run Exchange 2010 SP3 on-premise as well, within the same LAN.

Since we are new to Lync we cannot really say for sure which features based on EWS are really not working like listed here http://lyncuc.blogspot.de/2013/01/lync-and-exchange-web-services-ews-and.html

At least I can tell that Conversation History (that saving of chats within Outlook - which by the way is a complete bullshit in my opinion and cannot be called a real history), missed conversatoins and calls are working to me. Also presence status shown in Calendar is based on status in skype works fine. What I am missing indeed is, I never managed to see any of my via Outlook calendar planned  Skype-Meetings in my Meeting tab of the SfB client. Not sure when a meeting shoudl show up here, no idea if this has something to do with my autodiscover issue.

However, I am abit confused about this Error 32054 and have not figured out yet under which circumstances it occurs. It actually only ocurred in conjunctoin with my and another users account which do use SfB a bit more then others,we are still in evaluation process yet.

kind regards,

Dieter