Error accessing Website Microsoft Dynamics NAV 2015 Web Client

Dear Friends

Recently we configured 3 tier architecture (NAVSERVER, SQLSERVER & IIS Server on separate machines).
As per Microsoft documentation SPN registered & delegation setup done.

SPN
setspn - l domain\serviceaccount

ServerInstance/navserver:7046
ServerInsatnce/navserver.domain.com:7046

Delegation
DynamicsNAV navserver 7046
DynamicsNAV navserver.domain.com 7046
HOST navserver
HOST navserver.domain.com

But still we are getting the below error

'A server error has occurred, and the content cannot be displayed. Refresh the page or open a new browser window.'

Below is the event viewer message.

Error accessing Website Microsoft Dynamics NAV 2015 Web Client
URL: https://webserver/ServerInstance/WebClient/list.aspx?tenant=jp
Type: Microsoft.Dynamics.Nav.Types.NavServerNotFoundException
Message: A server was not found at "net.tcp://navserver:7046/ServerInstance/Service". Either the URL is incorrect or the server is currently not available.
StackTrace:
at Microsoft.Dynamics.Nav.Client.ConnectionEstablisher.ConfirmOpenConnectionRetry(ConnectFailedEventArgs connectFailedArgs, Exception exception)
at Microsoft.Dynamics.Nav.Client.ConnectionEstablisher.TestSpnSettings(ConnectFailedEventArgs connectFailedArgs)
at Microsoft.Dynamics.Nav.Client.ConnectionEstablisher.OpenConnection(ConnectionRequest connectionRequest, UserSettings& userSettings)
at Microsoft.Dynamics.Nav.Client.ServiceConnection.OpenConnection()
at Microsoft.Dynamics.Nav.Client.ServiceConnection.Initialize()
at Microsoft.Dynamics.Nav.Client.FormBuilder.BuilderSessionInitializer.OpenConnectionToServer()
at Microsoft.Dynamics.Nav.Client.FormBuilder.BuilderSessionInitializer.InitializeCore()
at Microsoft.Dynamics.Nav.Client.FormBuilder.BuilderSessionInitializer.Initialize()
at Microsoft.Dynamics.Framework.UI.UISession.Initialize()
at Microsoft.Dynamics.Nav.Client.Web.NavWebUISessionInitializer.InitializeCore(UISession session)
at Microsoft.Dynamics.Nav.WebClient.NavWebClientUISessionInitializer.InitializeCore(UISession session)
at Microsoft.Dynamics.Nav.Client.Web.NavWebUISessionInitializer.Initialize(UISession session)
at Microsoft.Dynamics.Framework.UI.Web.ShownFormTrackingUISessionInitializer.InitializeSessionAndTrackShownInitializationForms(UISession session)
at Microsoft.Dynamics.Framework.UI.Web.ShownFormTrackingUISessionInitializer.Initialize(UISession session)
at Microsoft.Dynamics.Framework.UI.Web.LogicalFormInitializer.InitializeSession(FormPropertyBag formBeingInitialized, ClientSession clientSession)
at Microsoft.Dynamics.Framework.UI.Web.LogicalFormInitializer.<>c__DisplayClass1.<Create>b__0()
at Microsoft.Dynamics.Framework.UI.LogicalOperationInvoker.InvokeAndHandleExceptions(Func`1 action, IExceptionHandler exceptionHandler)
Source: Microsoft.Dynamics.Nav.Client.ServiceConnection

---

Type: System.IO.IOException
Message: The write operation failed, see inner exception.
StackTrace:
at System.Net.Security.NegotiateStream.ProcessWrite(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.NegotiateStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at System.ServiceModel.Channels.StreamConnection.Write(Byte[] buffer, Int32 offset, Int32 size, Boolean immediate, TimeSpan timeout)
Source: System

---

Type: System.ServiceModel.CommunicationException
Message: The socket connection was aborted. This could be caused by an error processing your message or a receive timeout being exceeded by the remote host, or an underlying network resource issue. Local socket timeout was '00:00:59.9843793'.
StackTrace:
at System.ServiceModel.Channels.SocketConnection.Write(Byte[] buffer, Int32 offset, Int32 size, Boolean immediate, TimeSpan timeout)
at System.ServiceModel.Channels.BufferedConnection.WriteNow(Byte[] buffer, Int32 offset, Int32 size, TimeSpan timeout, BufferManager bufferManager)
at System.ServiceModel.Channels.BufferedConnection.Write(Byte[] buffer, Int32 offset, Int32 size, Boolean immediate, TimeSpan timeout)
at System.ServiceModel.Channels.ConnectionStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at System.Net.Security.NegotiateStream.StartWriting(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.NegotiateStream.ProcessWrite(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
Source: System.ServiceModel

---

Type: System.Net.Sockets.SocketException
Message: An existing connection was forcibly closed by the remote host
StackTrace:
at System.ServiceModel.Channels.SocketConnection.Write(Byte[] buffer, Int32 offset, Int32 size, Boolean immediate, TimeSpan timeout)

Please help to identify the problem.

Thanks & Regards
Nasheer.