Broken IMAP after Win 10 update to 1703 /Oct 5, 2017/

after Win 10 auto update to 1703 my IMAP account in EMClient no longer works. Stuck on synchronizing subfolders, no msgs downloaded.
Repair or delete and recreate account didnt help.
MailServer is OK, imap works fine on iPhone mail client.
emclient 7.1.30794.0

11:32:07 samo@****.london [IMAP]  MailClient.Accounts.ConnectionException: No server response within 30 second timeout. —> System.IO.IOException: No server response within 30 second timeout.
11:32:07    at MailClient.Imap.Base.Connection.Connect(Func`1 getStream)
11:32:07    at MailClient.Imap.Base.Connection.Connect(String receiveHost, Int32 receivePort, Boolean explicitSsl)
11:32:07    at MailClient.Protocols.Imap.ConnectionPoolEntry.Reconnect(CancellationToken cancellationToken)
11:32:07    — End of inner exception stack trace —
11:32:07    at MailClient.Protocols.Imap.ConnectionPoolEntry.Reconnect(CancellationToken cancellationToken)
11:32:07    at MailClient.Protocols.Imap.ConnectionPoolEntry.Connect(CancellationToken cancellationToken)
11:32:07    at MailClient.Protocols.Imap.ConnectionPool.AcquireConnection(Folder mailFolder, Boolean idle, Boolean forStore)
11:32:07    at MailClient.Protocols.Imap.ConnectionContext…ctor(ImapAccount account)
11:32:07    at MailClient.Protocols.Imap.Synchronizer.SynchronizeFoldersCommand.ExecuteInternal(WorkerStatus status)
11:32:07    at MailClient.Protocols.Imap.Synchronizer.ImapCommand.Execute(WorkerStatus status)
11:32:07    at MailClient.Commands.Command.Process(WorkerStatus status)

Have you tried deleting the account and setting it up again?