How do I find out what happened on this flight?
Issues in flight are more common than we think: engine shutting down in flight, fumes in cabin, ... Aircraft are huge pieces of engineering with many parts and sensors that can fail. Aircraft have many redundancies which most of the time allows for a safe landing. 

I tried to look on the avherald, a reliable and extensive source of aircraft reports, incidents and accidents, mainly fed by its owner and its users but the flight does not appear there. However you can appreciate the number of incidents occurring every day and this is a small part of them.