Naming Anything in an anvil

Whenever I name something in an anvil it resets instantly and goes back into the first slot of an anvil, using the anvils durability but the name is still the default name. Any Help because it has been bugging me for a bit I've been trynna nametag some of the zombie villagers I came across. btw i tried this in single player survival it works fine. but realms doesn't work.