Once registered, the domain and site cannot be deleted.
However, both the domain and site can be hidden. It is also possible to redisplay them.
・Hiding a domain
Click on Scan Menu > Domain List > Action > Hide (eye mark)
Click on Scan Menu > Domain List > Show Hidden Domains
・Hiding the site
Click on Scan List > Three Lines > Hide
Click on Scan List > Show Hidden Scans