• 4020997 Skype for Business Server 2015 Front-End service may crash in Windows Server 2016

This issue occurs because the certificate chain of a certificate that’s used by a Front-End server in a different pool cannot be validated.

• 4020994 Event ID 36023 is consistently logged on Multiple Front-End servers in a Skype for Business Server 2015 environment that enables CAC

When this issue occurs, the Bandwidth Policy Service event ID 36023 is logged on front-end servers every few minutes.

Note When this issue occurs, there is no actual function effect in Skype for Business Server 2015.

This issue occurs because the delay in call admission control (CAC) verifications for Inter-Cluster mode is set incorrectly.

• 4020993 DTMF tone isn’t played when some DTMF packets are dropped in the network in Skype for Business Server 2015

Consider the following scenario:

• You deploy a dual tone multi-frequency (DTMF) based Interactive Voice Response (IVR) application in a Microsoft Skype for Business Server 2015 environment.
• The application is developed by using Unified Communications Managed API.
• The application joins a conference.
• A user connects to the application, and then the user starts pressing DTMF digits.

In this scenario, the DTMF tone is missing.

This issue occurs because the Audio Video Multipoint Conferencing Unit (AVMCU) does not process the DTMF tone when the DTMF packets that carry the end of tone flag are dropped in the network.

• 4020991 Enables “move-csmeetingroom” cmdlet to move meeting room from on-premises to Online in Skype for Business Server 2015

• 4020987 The update to OcsMcu.msp can’t be applied when conferencing is disabled in Skype for Business Server 2015

This issue occurs because OcsMcu.msp tries to find the RTCASMCU and RTCAVMCU services that aren’t present because conferencing is disabled on the topology.

• 4020984 The ms-client-diagnostics header for application sharing scenario is not correctly formatted in Skype for Business Server 2015

This issue occurs because the incorrect type is put in the MediaType filed in a diagnostic blob that is added to the ms-client-diagnostic.

• 4020983 “sorry, I didn’t get that…” GVA announcement is triggered by external audio sources in Skype for Business Server 2015

The GVA announcement is triggered by external audio sources that sound like a dual tone multi-frequency (DTMF) tone.

Note The external audio sources that are identified are as follows:

• A Windows notification sound that’s confirmed to technically resemble the audio wave of the * DTMF tone.
• DTMF tones that are played by other phones in speaker mode nearby an audio device that’s connected to a meeting.

• 4019726 Call remains ringing on a PSTN phone when you click End Meeting in a Skype meeting in Skype for Business Server 2015

Consider the following scenario:

• You join a Skype meeting in a Microsoft Skype for Business Server 2015 environment.
• You invite a Public Switched Telephone Network (PSTN) number to the meeting.
• You click the End Meeting button before the PSTN callee takes the call.

In this scenario, the call continues to ring on the PSTN phone.

This issue occurs because the Audio Video Multipoint Conferencing Unit (AVMCU) cannot send the Cancel request to the Mediation Server.

• 4019725 Event ID 44005 and 44008 are logged when you try to leave a voicemail in Skype for Business Server 2015

This issue occurs because the Skype for Business Front-End service cannot connect to Domain Controller to read dial plan records.

• 4019724 You cannot join Skype meeting after you perform a pool failover in Skype for Business Server 2015

Consider the following scenario:

• You deploy two paired Front-End pools in a Microsoft Skype for Business Server 2015 environment.
• You perform a pool failover to fail over to the backup pool.
• A user creates a Skype meeting.
• You perform a pool failover to fail back to the primary pool.
• You join the meeting that’s created by the user.

In this scenario, you can’t join the Skype meeting.

This issue occurs because the conference data is inconsistent between the primary pool and the backup pool.

• 4019723 Agents in a Response Group can’t receive call after you invoke pool failover in Skype for Business Server 2015

Consider the following scenario:

• You deploy two paired Front-End pools in a Microsoft Skype for Business Server 2015 environment.
• You deploy Response Group Service (RGS) in the environment.
• You perform a pool failover by running the Invoke-csPoolFailover cmdlet between the two paired Front-End pools.
• After the pool failover, you run the Import-CsRgsConfiguration cmdlet to import the Workflows, Queue and Agents to the paired pool.
• You make a call to a Response Group.

In this scenario, the agents in the Response Group can’t receive the call.

This issue occurs because the value of the EnterpriseVoiceEnabled parameter isn’t set to True when you run the Import-CsRgsConfiguration cmdlet on the backup pool.

• 4019722 Event ID 30210 occurs when you try to leave voicemail in Skype for Business Server 2015

You cannot leave a voice mail message until the Skype for Business Front-End service is restarted in a Microsoft Skype for Business Server 2015 environment. Additionally, the following event is logged on the Microsoft Skype for Business 2015 Front End server.

Time: Date/Time
ID: 30210
Level: Warning
Source: LS Applications Module
Machine: SERVER Name
Message: Lync Server application is not responding and is being disconnected.

Application Uri ‘http://www.microsoft.com/LCS/ExumRouting‘ Cause: This can occur if the managed application is slow to respond to messages or if the server is under heavy load or the application has become unresponsive.
Resolution:
If the server load is too heavy, consider getting a faster machine or hosting fewer users on the server. If the application is slow, contact the author of the application.

This issue occurs because the ExUMRouting application is uninstalled from the TrustedServerList.

• 4015911 Pool failover fails when you have many conference directories in Skype for Business Server 2015

Consider the following scenario:

• You deploy two paired Front-End pools in a Microsoft Skype for Business Server 2015 environment.

• You create many conference directories.

• You start pool failover between the two paired Front-End pools.

• There are many meetings being scheduled during the pool failover.

In this scenario, the pool failover fails.

This issue occurs because a back-end SQL stored procedure takes more than one minute to sync the change of the conference directories.

• 4015910 Event ID 53106 "Unable to Save Message" occurs in Skype for Business Server 2015 Persistent Chat Server

When you configure the Persistent Chat Compliance service in a Microsoft Skype for Business Server 2015 multiple-server pool environment, the following event is logged on the Skype for Business Server 2015, Persistent Chat server.

Time: Date/Time
ID: 53106
Level: Error
Source: LS Persistent Chat Compliance Server
Machine: SERVER Name
Message: Unable to save message Date/Time PART ma-chan://domain.com/XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX X XXXXX to database due to exception:
CmdID: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX The server could not restore db connection within the allowed time (00:10:00) using connection string: Data Source=SERVER.domain.com\PCHATDB; Initial Catalog=mgccomp; Integrated Security=SSPI. at
at Microsoft.Rtc.Internal.Chat.Server.ServerCommon.Database.DbCommand.executeUntilSuccessOrTimeout[TR](Fun`2 executeDelegate, RetryInfo retryInfo)
at Microsoft.Rtc.Internal.Chat.Server.ServerCommon.Database.DbCommand.executeImp[TR](Fun`2 executeDelegate, Int32 retryTimeoutInMs)
at Microsoft.Rtc.Internal.Chat.Server.ServerCommon.Database.DbCommand.ExecuteNonQuery(Int32 retryTimeoutInMs)
at Microsoft.Rtc.Internal.Chat.Server.Compliance.ComplianceDataAccess.Save(RawComplianceData data)
at Microsoft.Rtc.Internal.Chat.Server.Compliance.ComplianceServer.Save(RawComplianceData data).

This issue occurs because of a race condition when you update tblComplianceParticipant table entries.

• 4015907 Update that enables simplified meeting join experience in Skype for Business Server 2015

This update enables the simplified meeting join experience and Skype Meetings App in Microsoft Skype for Business Server 2015.

For more information, refer to the following links:

• End-user help topic: Skype Meetings App help (Skype for Business Web App)
• Planning topic: Plan for Web downloadable clients
• Deployment topic: Deploy Web downloadable clients in Skype for Business Server 2015

• 4015904 Enables UCWA to populate "OTHER CONTACTS" and "FAVORITES" groups at first sign in to Skype for Business mobile app

• 4015902 Failed to start MatchMaking service and its dependencies if FIPS for RGS is enabled in Skype for Business Server 2015

This issue occurs when Federal Information Processing Standards (FIPS) for Response Group Service (RGS) is enabled in a Microsoft Skype for Business Server 2015 environment.

Additionally, when you establish application endpoints, you may see the following exception:

sip:RtcApplication-XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX@domain.com
sip:RtcApplication- XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX@domain.com
sip:RtcApplication- XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX@domain.com
Exception: System.Reflection.TargetInvocationException – System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> System.InvalidOperationException: This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms.
at System.Security.Cryptography.SHA512Managed..ctor()
— End of inner exception stack trace —

at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Security.Cryptography.CryptoConfig.CreateFromName(String name, Object[] args)
at System.Security.Cryptography.SHA512.Create()
at Microsoft.Rtc.Acd.Common.ConsistentHash`2..ctor(Func`2 nodeToHashKeyConverter, Func`2 requestToHashKeyConverter, Int32 virtualNodesMultiplier)
at Microsoft.Rtc.Acd.MatchMaking.PresenceProvider.PresenceComponent.Initialize(IReadOnlyCollection`1 presenceEndpoints, Int32 maxRgsAgentsPerPresenceWatcher)
at Microsoft.Rtc.Acd.MatchMaking.MatchMakingService.Start(IReadOnlyCollection`1 presenceEndpoints)
at Microsoft.Rtc.Acd.AepManager.StartMMAndItsDependencies(IReadOnlyCollection`1 presenceEndpoints)
Cause: Failed to connect to Front End server or the Front End server is misconfigured.
Resolution: Check the Front End server for errors.

This issue occurs because the MD5 and SHA512Managed classes don’t have FIPS enabled.

• 4015901 Calls to RGS may fail after an in-place upgrade from Lync server 2013 to Skype for Business Server 2015

In Skype for Business Server 2015, the default design is changed to use three Presence Watcher contact objects (instead of one Presence Watcher contact object in earlier versions). The service startup failure is introduced to prevent an issue in which the service has started, but calls to RGS fail with "500 Internal Server error", because only one Presence Watcher contact object is found after the start of the RGS service.

• 4015900 Enables “VoicemailOnBusy” ActionType to be set for Exchange Online users in Skype for Business Server 2015 Busy Options

Consider the following scenario:

• You have enabled Busy Options feature in a Microsoft Skype for Business Server 2015 environment that has Cumulative Update 2 (Version 6.0.9319.235) or later versions installed.
• You enable a user for Microsoft Exchange Unified Messaging (UM) On-Premises.
• You move the user’s mailbox to Exchange Online.
• You enable the user for Exchange UM Online by assigning on-premises hosted voice mail policy.
  Note The on-premises attributes for this user are now set as follows:
  • ExUmEnabled=False
  • HostedVoiceMail=True

In this scenario, you can’t set the BusyOnBusy option to an ActionType of VoicemailOnBusy for this user.

Additionally, you receive the following error message:

PS C:\Users\SfBadmin> Set-CsBusyOptions -Identity "Ken Myer" -ActionType VoicemailOnBusy
Set-CsBusyOptions : Voicemail is not enabled for Identity "Ken Myer".
At line:1 char:1
+ Set-CsBusyOptions "Ken Myer" -ActionType VoicemailOnBusy
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [Set-CsBusyOptions], BobException
+ FullyQualifiedErrorId : Microsoft.Rtc.Management.Bob.Cmdlets.BobSetConfigurationCmdlet

This issue occurs because the VoicemailOnBusy action type was designed to support only on-premises Exchange UM deployments.

• 4015899 "Busy Options" feature doesn’t check the second incoming call in Skype for Business Server 2015

Consider the following scenario:

• You have enabled Busy Options feature for internal Skype for Business users in a Microsoft Skype for Business Server 2015 environment.
• You have the following restriction in your manifest file:
  domainSupported="true"
• You are in a call with another federated user.
• A user is trying to call you.

In this scenario, you find double toast notifications.

This issue occurs because calls to federated users are not tracked by Busy Options when the domainSupported parameter is set to true.

• 4015898 RGS agents may stop receiving calls after you run the “Enable-CsTopology” cmdlet in Skype for Business Server 2015

This issue occurs because the presence watcher is reset when the Enable-CsTopology cmdlet is invoked.

• 4015893 Enables delegate management feature for Unified Communications Web API in Skype for Business Server 2015

To get this update, install the May 2017 cumulative update 6.0.9319.281 for Skype for Business Server 2015, core components.

Note After you install this update, run the following Skype for Business management PowerShell command to enable the feature:

‘Set-CsPlatformServiceSettings –EnableDelegateManagement $true’