If you are getting notifications from NetLookupSearch, then your Mac is infected with adware. NetLookupSearch is adware for Mac.
NetLookupSearch changes setting in your Mac. First, NetLookupSearch installs a browser extension in your browser. Then, after NetLookupSearch hijacks your browser, it modifies settings in the browser. For example, it changes the default home page, modifies search results, and displays unwanted pop-ups in your browser.