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