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If you are running a RedHat or CentOS system and you have upgraded Nmap or went to a previous version sometimes it is necessary to reset the SUID on the binary. You can do this by running the following command:
chmod u+s /usr/bin/nmap
User attempted to view a resource which does not exist error
This typically occurs when discovering a single device and the discovery completes. When clicking the refresh discovery button on the page and the discovery completes the discovery disappears