Error at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

Hi,

a client intermittently gets the following error when receiving e-mails using POP3:

15:31:52 A.van.Harten2@kpnplanet.nl [POP3] MailClient.Accounts.SocketException: Fout opgetreden bij het ontvangen van account A.van.Harten2@kpnplanet.nl : Unable to read data from the transport connection: Een verbindingspoging is mislukt omdat de verbonden party niet correct heeft geantwoord na een bepaalde tijd, of de gemaakte verbinding is mislukt omdat de verbonden host niet heeft geantwoord…
at MailClient.Protocols.Pop3.Pop3ReceiveCommand.Execute(WorkerStatus status)
at MailClient.Commands.Command.Process(WorkerStatus status)
EnqueuedStackTrace =
at MailClient.Protocols.Pop3.Pop3Account.<>c__DisplayClass7_0.b__0()
at MailClient.Protocols.Common.AccountBase.RunIfOnline(Action actionIfOnline, Action actionIfOffline)
at MailClient.Protocols.Pop3.Pop3Account.ReceiveAsync(Action1 receivedItem, Action1 completed, CancellationToken cancellationToken)
at MailClient.Accounts.BindingAccountBase.Receive()
at MailClient.Accounts.AccountManager.ReceiveAllInternal()
at MailClient.Accounts.AccountManager.SendAndReceiveAll()
at MailClient.Program.<>c.b__223_0()
at MailClient.Accounts.AccountManager.<>c__DisplayClass82_0.b__0(Object )
at System.Threading.QueueUserWorkItemCallback.<>c.<.cctor>b__6_0(QueueUserWorkItemCallback quwi)
at System.Threading.ExecutionContext.RunForThreadPoolUnsafe[TState](ExecutionContext executionContext, Action`1 callback, TState& state)
at System.Threading.QueueUserWorkItemCallback.Execute()
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

Any ideas?