InstantMessagingCall not fired after change ip of the bot Server

Hi, I've developed and deployed an IM bot using UCMA 3.0 against a lync2010 server, the bot was running ok for several months, but suddenly stops responding, in fact all initialization is being done ok, with no errors, but Event of InstantMessagingCall Received is never fired, but changes of states/note are being performed

Another server with the same code (but diferent applicationURI / gruu, name, etc) but same lync server is still running ok.

The only change that was performed was the migration of the IP and Net of the bot server where the service is deployed (is not posible revert the change)

I'm running out of ideas on how to diagnose the trouble/ what more can I do for testing ?

Below are part of the code, that i'm using for testing

  Dim gruu As String = "sip:xxxxxxx.com@yyyy.com;gruu;opaque=srvr:nnnnnn.application:sdsfsdfsdfsdfsdfsdfsdfsdfsdf"

	Dim cert As New X509Certificate2
    cert.Import("xxxxxxx.com.com.pfx", "pppp", X509KeyStorageFlags.DefaultKeySet)

    Dim platformSettings As ServerPlatformSettings
    platformSettings = New ServerPlatformSettings("nnnnnn.application", "xxxxxxx.com", 5061, gruu, cert)

    ThisCollabPlatform = New CollaborationPlatform(platformSettings)
    ThisCollabPlatform.InstantMessagingSettings.SupportedFormats = InstantMessagingFormat.PlainText Or InstantMessagingFormat.HtmlText Or InstantMessagingFormat.Gif
    ThisCollabPlatform.EndStartup(ThisCollabPlatform.BeginStartup(Nothing, Nothing))
    
	Dim applicationUri As String = "sip:xxxxxxx.com@yyyy.com"
    Dim ocsFqdn As String = "lyncxxxxxx.com"
	Dim settings As ApplicationEndpointSettings
    settings = New ApplicationEndpointSettings(applicationUri, ocsFqdn, 5061)
    settings.PresenceBasedScreeningDisabled = False
    settings.UseRegistration = True

	ThisEndpoint = New ApplicationEndpoint(ThisCollabPlatform, settings)
    ThisEndpoint.RegisterForIncomingCall(Of InstantMessagingCall)(AddressOf InstantMessagingCallReceived)
    ThisEndpoint.EndEstablish(ThisEndpoint.BeginEstablish(Nothing, ThisEndpoint))
    
	PublishState(Available, "Esperando", "In Service")
.....


  Sub InstantMessagingCallReceived(ByVal sender As Object, ByVal e As Microsoft.Rtc.Collaboration.CallReceivedEventArgs(Of Microsoft.Rtc.Collaboration.InstantMessagingCall))

    Try
      PublishState(Busy, "Alguien me escribe", "")
	  console.writeline("{0} Start Call {}", e.Call.CallId, e.ToastMessage)
    Catch ex As Exception
      Console.WriteLine(ex)
    End Try

  End Sub

Any suggestion/recommendation will be really appreciated