Why does MS stop you from walking?

Excuse me, but could you elaborate on why Multiple Sclerosis, or MS, can impede one's ability to walk? I understand it's a complex neurological disorder, but I'm curious about the specific mechanisms at play that can cause such a significant impact on mobility. Is it due to damage to the nerves that control muscle movement? Or is it more related to the communication between the brain and these muscles? I'm interested in understanding how MS affects the body's ability to walk and the challenges it poses for those living with this condition.