What is the major hurdle for planets orbiting closely around active M dwarfs?

Answer

Powerful flares emitting intense bursts of radiation

M dwarfs are prone to powerful flares, sending out energetic bursts of ultraviolet and X-ray radiation that can strip away atmospheres or sterilize surfaces.

What is the major hurdle for planets orbiting closely around active M dwarfs?
astronomystarsexoplanetslifeHabitability