Ok i deactivead auto-cron job under settings, create a windows scheduled task to start a batch file like "C:\PHP\php.exe" -f C:\inetpub\wwwroot\osTicket\api\cron.php
i start a cmd and typed these command manually 
Nothing happened, no php error, only that aboved with mbstring.
And debug mode says:
Mailsettings are right AFAIK, i send testmail to my mailsystem, received the mail directly.
