The Serpent was able to deceive the woman who was to become Chavah the lifegiver because the doctrine that she had been given about the tree of knowledge of good and evil was wrong, she was told that she should not touch it because then she would die, we are not told who told her this but it was obviously not Yah.
Chavah was learning, probably from Adam, how to relate to the environment around herself, but the untruth/partial truth about the function of the tree of knowledge made her vulnerable to deception.
When mankind starts to embroider Yah’s truth with his own bells and whistles, he is creating spiritual ammunition for satan to use against us.