Naturally it is both. Austen examines both negative societal pressures and our internal biases that lead us to mistakes. Darcy and Elizabeth have to overcome all of these before they can allow themselves to fall in love and get married.
Elizabeth's conflicts: 1. marrying for love or marrying for money/security to help her family (Mr. Collins is the threat, Charlotte actually takes this path) 2. Overcoming her own pride (or "vanity") in her perceptions so that she can see her mistakes in judging Wickham and Darcy
Darcy's conflicts: 1. Societal pressure to marry with a girl from a rich, high-classed and well behaved family (not Elizabeth) 2. Learning to recognize his own arrogance
Then there are other external conflicts- Lydia's elopement, Catherine de Bourgh's machinations, Caroline Bingley as a rival...
A book never has one conflict, there will be many :)
