Why has Bolivian President Evo Morales resigned and fled?

The South American nation of Bolivia is in a state of chaos following a general election on October 20 2019. Evo Morales, the country's first indigenous president, who has been in power since 2006, has resigned after questions were raised over the validity of his recent re-election. He's now in self imposed exile in Mexico and has been replaced by his fierce critic, opposition senator Jeanine Áñez. The interim president is pledging to steer the country to more elections soon. But with concerns over her conservative views, and escalating tension on the streets, some speculate that continued instability could pave the way for Morales' return. So what are the hopes for a second round of free and peaceful elections soon?