If you are getting notifications from SkilledNetwork, then your Mac is infected with adware. SkilledNetwork is adware for Mac.
SkilledNetwork changes setting in your Mac. First, SkilledNetwork installs a browser extension in your browser. Then, after SkilledNetwork 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.