Popup 'Password Required'

Suddenly on one of my email accounts the " Password Required pop up" shows up. Nothing was changed since yesterday evening, emclient is still the same and I can log in on my browser-email-function. The provider of both emailaccounts is Office365.

Log (xxx is my emailaddress):
9:11:39 AM xxx@xxxx.xx [Exchange Web Services] MailClient.Accounts.AuthenticationAbortedException: Authentication aborted
at MailClient.Protocols.Exchange.ExchangeGenericCommand.Execute(WorkerStatus status)
at MailClient.Commands.Command.Process(WorkerStatus status)
EnqueuedStackTrace =
at MailClient.Protocols.Exchange.ExchangeFolderSynchronizer.GoOnlinePre()
at MailClient.Protocols.Exchange.ExchangeAccount.GoOnlineInt()
at MailClient.Protocols.Common.AccountBase.ChangeOnlineState(Boolean online, OfflineReason offlineReason)
at MailClient.Protocols.Common.AccountBase.GoOnline()
at MailClient.Accounts.AccountList.<>c__DisplayClass19_1.b__1()
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.<>c.<.cctor>b__277_0(Object obj)
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
at System.Threading.Tasks.Task.ExecuteEntryUnsafe(Thread threadPoolThread)
at System.Threading.Tasks.Task.ExecuteFromThreadPool(Thread threadPoolThread)
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
GUIStatus_Exception_Reported = True

Anybody?

I changed the password in outlook, but that did not do the work. Is there canybody who can help me with this?