Thanks for coming by and I'm sorry to hear you can't seem to unlock Reksa's good ending ><
The reason could be because you don't have enough affection points. Have you tried following the walkthrough? The link is here: https://lemmasoft.renai.us/forums/viewtopic.php?t=36095 (click and drag your mouse over the white box to see its content).
I hope this could help you to get it and so you can catch up with your rest ^.^-