DIAGNOSIS The drill's motor controller or electronic clutch is preventing operation due to a fault detection. The most common cause is a damaged or obstructed chuck.
FIX Inspect the chuck and spindle. Remove the battery. Manually rotate the chuck. Check for foreign material. If it rotates, reinstall the battery and attempt to run the tool in a non-hammering mode with no load. If the chuck is visibly damaged or wobbles, it requires replacement.
IF THAT DIDN'T WORK The issue is internal. The primary suspects are a failed motor controller board or a damaged trigger assembly. This requires professional service at a Milwaukee service center.
HEADS UP Do not continue to pull the trigger if the tool clicks repeatedly. This can overheat and permanently damage the motor or electronics.