The video isn't showing for me. Well, I'm guessing you're in a Pokemon Center, tried to save, then the "unable to save" message popped up.
Anyhow, restart your switch, make sure the game is closed, then use JKSV to import save, then launch game and save.
Also make sure the save you're importing has a functional main, backup and untouched poke_trade (only if this file is present in your dumps) Make sure that Edizon is closed and has remained closed.
Better yet, if you want to edit a save, edit a save that was dumped with JKSV, then import that.