After installing Norton 360 on my iMac running Catalina (after being pestered to do so by Telus), web browsing stopped functioning properly. I tried the various "fixes" offered on the internet, such as things to do in Norton settings, but neither Chrome nor Safari functioned properly. Could not connect to websites. Eventually I deleted Norton 360 from this machine. And now everything works properly.
In my limited experience, Norton and MacOS never get along. If you really want an anti-virus program, search one specific to Mac.
I had to back-track (via time machine/back up) and revert to my earlier system: good to know that worked.
and yet.. I posted related topic re: Norton: "Telus keeps sending promo to Load Norton VPN" Seems to be a huge push on from Telus to support NORTON products.