Which website you get redirected to - iport.travelport perhaps? The good news (failing any other attempt) is that you will now be able to use the 2 self check-in kiosks in the departures area, they’ve only been recently installed and will save you a significant amount of time as on-line check-in doesn’t always work (I often fly Croatia but also Air Serbia and check-in departing Sarajevo is only possible via airport’s website/iPort, often leading to error messages, seat selection unavailable and the likes).

G