Whats is Okonkwos tragic flaw in chapter 13 ?

As day brokes, men come and destroy Okonkwo's home. They kill his animals and set fire to the buildings. They bear no malice to Okonkwo, but the laws of the Igbo must be obeyed. Obierika is sorry for his friend's misfortune. He is a thoughtful man, and he tries to think out why his friend should suffer. He also thinks of the twins his wife bore long ago, and how he had to abandon them to certain death. He arrives at no answers. But the beginning of Okonkwo's tragedy is a complete accident. It is a moment of blind chance that drives Okonkwo from his homeland. The greatest loss is more than material: Okonkwo's faith in the power of hard work is shaken. His will and strong arm are unable to prevent this disaster. As a middle-aged man, Okonkwo is being forced to start over again.

Although the event is an accident, it should also be remembered that Ezeudu was the man who warned Okonkwo not to take hand in Ikemefuna's death. The disaster, a seeming accident, seems to confirm the fears of Obierika, who warned Okonkwo that the earth goddess did not smile on Okonkwo's participation in Ikemefuna's murder. The tragic flaw in Okonkwo was highlighted long before.

To be more specific I think Okonlwo's tragic flaw was his pride and stubbornness made clear in the killing of his son Ikemefuna. Ezeudu was the man who warned Okonkwo not to take hand in Ikemefuna's death. Okonkwo did not heed this advice, instead doing what he thought looked to be strong in appearance and deed. In doing this he unravelled his destiny. He angered the Earth Goddess but more importantly, destroyed himself.