Did you look it up? How closely did you read?

https://professorbuzzkill.com/einstein-insanity-qnq/

Alas, Buzzkillers, quotes like this seem to attach themselves to Einstein at the speed of light, and there’s no evidence he ever said it. (By the way, two other brainiacs and quote attractors, Ben Franklin and Mark Twain, are also credited with coining this idea.)

The “definition of insanity” quote first appeared in 1981, in a document published by Narcotics Anonymous. It was a sort of guide book for addicts who trying to overcome their disease, and it warned its readers that, “insanity is repeating the same mistakes and expecting different results.” Narcotics Anonymous was trying to convince its members that continuing to use narcotic drugs and expecting to be able to stop on their own was folly.