synchro

The Calendar can not be synchronized anymore. Following error message is shown : 

qte 

CalendarApp.CalDavProvider.DavAccountRequestException: Nicht zulässig (403).

Der Antwortstatuscode zeigt keinen Erfolg an: 403 (Forbidden). : <?xml version='1.0' encoding='UTF-8'?><D:error xmlns:D="DAV:" xmlns:cosmo="http://osafoundation.org/cosmo/DAV"><cosmo:forbidden/></D:error> ---> CalendarApp.Common.Net.HttpException: Nicht zulässig (403).

Der Antwortstatuscode zeigt keinen Erfolg an: 403 (Forbidden). ---> System.Exception: Nicht zulässig (403).

Der Antwortstatuscode zeigt keinen Erfolg an: 403 (Forbidden).
at System.Runtime.InteropServices.McgMarshal.ThrowOnExternalCallFailed(Int32, RuntimeTypeHandle) + 0x21
at __Interop.ComCallHelpers.Call(__ComObject, RuntimeTypeHandle, Int32, Void*) + 0xbe
at __Interop.ForwardComStubs.Stub_2[TThis, TResult](__ComObject, Int32) + 0x37
at Windows.Web.Http.HttpResponseMessage.EnsureSuccessStatusCode() + 0x18
at CalendarApp.Common.Net.CalendarHttpClient.<ExecuteRequest>d__29.MoveNext() + 0x82d

--- End of inner exception stack trace ---
at CalendarApp.Common.Net.CalendarHttpClient.<ExecuteRequest>d__29.MoveNext() + 0x18b0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x21
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0x70
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x38
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task) + 0x17
at CalendarApp.CalDavProvider.DavHttpWebRequest.<Request>d__12.MoveNext() + 0x76f

unqte 

What has to be done in order to solve this problem ?! 

Pleased to hear 

Best regards 

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