No such host is known is a DNS error indicating that the name of the device that ConfigMgr has could not be resolved in DNS. You have a couple of options for working around DNS issues:
- Don't choose the Use FQDN option in Configure Recast RCT. This will cause Recast to use the short name instead of the FQDN when connecting to devices.
- Choose the Use IP Address Instead of Computer Name option, along with the Verify Computer Name in WMI option. This will tell Recast to use the IP address that ConfigMgr has in hardware inventory to try to connect to the device and bypasses DNS altogether. The Verify Computer Name in WMI option is there to protect against out of date IP addresses in ConfigMgr's inventory, so that you don't accidentally run actions on the wrong devices.