Deleted IP won't rescan.

Have SonicWALL at 192.168.2.254. It appeared as unknown device. I deleted it and then realized I didn't have SNMP configured correctly on it. I fixed that but does not show up under normal scan; not even as UNKNOWN. I created a separate scan for just its IP and the TEST showed successful. Scan still does not show any result. Seems like deleting the IP address from discovered devices has it in some type of exclusion group; yes?

Thanks,

Troy