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In Microsoft Skype for Business Server 2019 and Skype for Business Server 2015, when a user signs in to one of the UCWA mobile clients (Skype for Business for Android or Skype for Business for iOS), the UCWA service crashes and the following event ID 20003 is logged:

Log Name:      Lync Server

Source:        LS UCWA​

Date:          DateTime

Event ID:      20003​

Task Category: (1099)​

Level:         Error​

Keywords:      Classic​

User:          N/A​

Computer:      ComputerName  ​


UCWA encountered an unhandled exception.​

Exception: System.IO.InvalidDataException: Found invalid data while decoding.​

at System.IO.Compression.Inflater.Inflate(Byte[] bytes, Int32 offset, Int32 length)​

at System.IO.Compression.DeflateStream.Read(Byte[] array, Int32 offset, Int32 count)​

at System.Xml.XmlTextReaderImpl.InitStreamInput(Uri baseUri, String baseUriStr, Stream stream, Byte[] bytes, Int32 byteCount, Encoding encoding)​

at System.Xml.XmlTextReaderImpl..ctor(String url, Stream input, XmlNameTable nt)​

at System.Xml.Serialization.XmlSerializer.Deserialize(Stream stream)​

at Microsoft.Rtc.Internal.Ucwa.Core.ApplicationInstanceData.FromMobilityCategoryData(Mobility mobility)​

at Microsoft.Rtc.Internal.Ucwa.Core.MobileApplicationData..ctor(Mobility rawMobilityData)​

at Microsoft.Rtc.Internal.Ucwa.People.MeManager.MePresenceNotificationReceived(Object sender, LocalPresentityNotificationEventArgs args)​

at Microsoft.Rtc.Signaling.EventWorkitem`1.Process()​

at Microsoft.Rtc.Signaling.WorkitemQueue.ProcessItems()​

at Microsoft.Rtc.Signaling.SerializationQueue`1.ResumeProcessing()​

at Microsoft.Rtc.Signaling.SerializationQueue`1.ResumeProcessingCallback(Object state)​

at Microsoft.Rtc.Signaling.QueueWorkItemState.ExecuteWrappedMethod(WaitCallback method, Object state)​

at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)​

at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)​

at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()​

at System.Threading.ThreadPoolWorkQueue.Dispatch()​

Cause: An unhandled exception happened.​


Restart the server. If the problem persists contact product support


To fix this issue, install one of the following updates:

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