What mode was selected? Recirculation is disabled if Defrost/Defog mode is selected. When you say it "flashes blue" do you mean the blue light blinks or does it stay on? If it stays on, but the recirculation door doesn't open, the corresponding actuator could be bad. They frequently fail, but I've yet to hear of one that stopped working altogether. Usually, it keeps moving for a couple minutes after the ignition is switched off. If yours has been doing that for a while before this it may have just finally stopped working.In my 2017 Limited, when I depress the button it flashes blue but never engages. It used to work properly and I change the cabin filter annually. Any ideas?