upload mbr image failed http error code 0

upload mbr image failed http error code 0

I get the error as in title (and the whole text of error below) when I try to get device image:
Error in Scheduled Packes:
Make sure that network is up and flash or harddrive is connected to the device properly
disable Anonymous authentication if enabled on softwareRepositary under MyWDM virtualDirectory

I can successfully deploy e.g. VNC into WYSE thin client. We are using WYSE Device Manager 4.8.5 and C90LEW clients

I try to disable and enable Anonymous authentication on IIS FTP site - does not work for me