hi @Tuwharetoa ,
In past this has been because the Matchmaking region in Fornite Creative has not been set correctly. Try setting this to NA Central (NC) then run any known working published Island.
Leave FNC running and go into UEFN and try and run matchmaking in your area.
Remember to turn off/remove any VPN software as Fornite/UEFN will lock out matchmaking on this.
Check you Windows Defender settings.