Disc brake noise can be a matter of some water or dirt temporarily getting on the rotors. If previously quiet brakes start making a noise, clean the rotors with isopropyl alcohol or mild soap and water. For eTap AXS disc brake troubleshooting assistance, see the guide here.
If the noise is more persistent and remains long term, the pads may be contaminated, or improper bed-in left inconsistent layers of pad material on the rotor surface. The solution is the same in either case: replace the pads and rotors, and carefully follow the bed-in process found here for quiet operation.