DIAGNOSIS The overload protection is kicking in. The motor is detecting too much resistance, usually because the ingredients are too thick or frozen, or the battery is weaker than it should be.
FIX Thin out your mix. Add more liquid (water, milk, juice) so the contents can move freely. If using frozen fruit, let it thaw slightly or use less of it. Don't fill the jar past the 14 oz max line. Try a shorter blend: pulse in 1-2 second bursts instead of holding the button, allowing the ingredients to settle between pulses.
IF THAT DIDN'T WORK The battery might be degraded and can't deliver peak power anymore. Try using it immediately after a full charge. If it still stalls, the battery is likely nearing the end of its lifespan.
HEADS UP This isn't a full-sized blender. It's designed for pre-chopped soft fruits and liquids, not crushing ice cubes or whole frozen chunks. Overloading it repeatedly will permanently shorten the motor and battery life.