The correct sentence is: You may notify me or John Doe.
Here's why:
* "Myself" is a reflexive pronoun. It should be used to refer back to the subject of the sentence. In this case, the subject is "you." So, "myself" doesn't make sense here.
* "Me" is the object pronoun. It's used when the pronoun is the object of a verb or preposition. In this case, "me" is the object of the verb "notify."
Therefore, "You may notify me or John Doe." is the grammatically correct sentence.