An id is meant to be a unique identifier. You can't have two unique identifiers on the same span, or same anything.
You can use multiple classes however - .user, .Maxi, .John, etc. But you don't give any styles for your Maxi, John, Henry etc styles. So without them, there will be no visible change.
It's just possible that the browser is trying to apply the styles for the last id you use, and in each case there are no styles for that id.