Whether tragedy is a result a fate or fault depends on your philosophy. If you are a fatalist, you believe that all fate is predetermined and it does not matter what a person does.
The idea of a tragic flaw dates back to Aristotle’s concept of hamartia, which we usually translate to “tragic flaw,” implying that a character has a fault that causes his downfall. However, this may not be accurate.
Yet a reevaluation of the term has interpreted it as “missing the mark,” an idea that suggests tragedies occur when characters simply misunderstand their place in the world. (enotes tragedy)
Therefore we have to look to our own analysis of life, or a character’s actions. For example, in Macbeth the title character does face destruction. However, you can interpret it as coming from a tragic flow of ambition, or from manipulation by outside forces including fate.