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.
