Harmoines sound dissonant no matter what I do

So, I’m trying to do an English cover of Mirai by Garnidelia, and I’m not sure if I’m just doing it wrong or if this is just how this software works but for whatever reason my harmony line sounds dissonant, especially when I have the instrumental going. Folder with both A Capella and With BGM samples

Some notes

  • I haven’t actually tuned the harmony line that much, while I’ve basically tuned the melody. Maybe that’s the problem?
  • My Music theory knowledge is minimal, but I at least know how keys work. But I’m not sure I did it right.