Villagers cant spawn in our realm. despawn instantly after we spawn them

Villagers won't spawn our 1.15.2 realm, None of the villagers have had any villagers in them, only iron golems and cats, we tried curing a zombie villager but as soon as he turned into a villager it despawned, i even put a name tag on the zombie villager. We tried using spawn eggs which would spawn a villager and then instantly despawn. I can spawn villagers in a single player world just fine but the realm just wont let us have villagers. Any help would be greatly appreciated. cheers