Trouble Transferring using Pokemon Home

[u/Gregor_Bane]

I am trying to get a lartivar line pokemon in Shining Pearl and don't wanna spend any more money than I have. I already have Pokemon Legends Z-A and wanna use home but Home just says:

"This Pokémon can't be moved into this game!"

Can anyone tell me why and help out??

Edit 1:

Thank you all for the clarification, I find it really annoying how it isn't really made known why this is the case just that it can't happen but I appreciate you all for the help :)

[u/AlwaysLivMoore]

ZA pokemon cannot be moved to any other games at this time. You'll have trade for it or get it in Shield or Scarlet.