SmarterMail – No connection could be made because the target machine actively refused it 127.0.0.1:17001

Today i notice my site don't send notice mail to me.
So i go to my mail control panel and yes this error came to me. - -'

after research i found solution to repair .NET 4.0 Client. here we go.

Windows > Control Panel > Programs > Programs and Features

Uninstall/Change on "Microsoft .NET Framework 4 Client Profile"

Repair on that and reboot.

Anything work again.