Last Day on Earth: Survival – I can’t start a trial in the Commune, what "previous trial" should I complete?

Each trial of each of the three characters, Marcus, Otis and Sophia, consists of three consecutive battles. The trial is considered completed if you won all three battles or if you stopped at any time and took reputation and resources (by clicking “Take all” button).If you haven’t done any of the above, and if you still have resources in one of the altars (award that you didn’t take), then you will not be able to start another trial via another altar.

Last Day on Earth: Survival Game GUIDE