While you were replying I updated my comment with more info.
It looks like your lemmy.blåhaj account is the owner (top mod) for !Fallout@lemmy.world and you added this piefed.blåhaj account as a mod ~30 minutes ago.
And your lemmy.blåhaj account is the only mod at !Falloutmods@lemmy.world so you should be able to add this account there.