5 String banjo string buzzing?

[sheltonbenjamin]

I got a 5 string banjo from amazon the other day, but when i tuned it up i noticed that the highest string buzzes, even when i have no finger on fret.
i also noticed other strings did a similar buzzing hwne i had my finger on higher frets, so it seems like the higher the note, the more the buzzing.
does anyone know how i can fix this?
i heard something abotu a truss rod, if this is te case how can i adjust it?
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