Hi, this is most probably caused by some specific settings of your network (perhaps your router has some security system of its own).
To disable the notifications please follow these instructions:

  • open the Avast Mobile Security app
  • tap the “three-lines icon” in the upper left corner of the screen to bring the menu
  • in the menu select “Settings”
  • tap on “Notifications”
  • right there turn the “Potential Wi-Fi issues” off