DIAGNOSIS The thermal overload protector in the motor base is tripping. This is caused by motor overheating or a voltage issue.
FIX Unplug the unit completely. Let it cool for at least 45 minutes. Plug it into a different, dedicated wall outlet. Ensure you are not overfilling the pitcher. Try a shorter blend cycle on a lower speed.
IF THAT DIDN'T WORK The motor brushes may be worn out. This requires disassembly of the motor housing to inspect. For this model, consider professional repair or replacement.
HEADS UP Do not run the blender continuously for more than one minute. Let it rest for a minute between cycles to prevent overheating.