Sounds like a link pointer failure. I am assuming you mean the navigation tool bar not the dropdown tool bar.
If you have used the drag and drop method to add it to the tool bar, it may have been done several times, possibly by other users (assuming more than one person has access to it).
Does the macro still work when it is clicked? I’m guessing it does, hence your question.
Open VBA/macro creation sheet and look through all the macros to see if it is listed there.
Does it work if you click each one in turn? If it doesn’t then remove the ones that don’t work, as it is the link that is broken. Might be why extra buttons were added for the same macro.
Try right click on the macro link in the tool bar and select delete. This should just remove it from the tool bar, but not delete it from the macros list in the vba sheet. You might have to do it for all instances of the macro on the tool bar.