Diagnosis
The machine is stuck in its automatic descaling reminder mode. It won't brew until you acknowledge or bypass the reminder.
How to Fix It
This is a button sequence, not a repair. Here's what you do: 1) Make sure the machine is on and the water reservoir is full and seated. 2) Press and HOLD the 8oz and 12oz brew buttons at the SAME TIME for about 5 seconds. You should see all the lights flash. 3) Let go. The 'add water' light might flash. If it does, lift the reservoir off and put it back on. The machine should now reset and the brew buttons will be responsive again.
If That Didn't Work
Try a full power reset. Unplug the machine from the wall. Wait a full 2 minutes. While it's unplugged, press and hold the power button for 30 seconds to discharge any leftover power. Then plug it back in and turn it on.
Heads Up
That button combo is the official reset for this model. It doesn't erase the descaling timer permanently—you'll still need to descale eventually—but it gets you brewing again.