You can't get into any of the expert dungeons unless you're A) level 60 and B) have 145 ilvl. I suppose lodestone might not have updated your level if you just dinged 60 yesterday, but you can't get in with Zeta + Augmented Poetics. Unless you changed once you got in (after having 145), in which case I'm surprised you weren't kicked.

Did you mean one of the leveling dungeons, like Dusk Vigil or the Vault?