Blue Xmas Christmas icicle lights string (Dereham NR19)

Just switched them on and it looks like 1 or 2 of the bulbs don’t come on but the vast vast majority are on as you can see from the picture. They are the icicle hanging lights - house picture included is a representation (not actual icicles). For outdoor or indoor. They are on a random flashing pattern. They are 9mt long and plug in to a normal 3-pin socket.