Why didn't Protestants unite with the Orthodox against Papal primacy after the Reformation?

Is there some doctrinal, historical or political reason that prevented this natural alliance from taking place? Are Protestants against the notion of the [Pentarchy](https://en.wikipedia.org/wiki/Pentarchy) in general and not just against the Papacy? If so, does this mean they see the Church as corrupt *already* before Emperor Justinian formed the Pentarchy?