"This In-App purchase has already been bought. It will be restored for free"

I was recently doing a discord nitro giveaway on my server, the intention was for me to buy multiple ones, yet I bought one and for some reason a pop up keeps appearing saying "This In-App purchase has already been bought. It will be restored for free" I don't know how to fix this, and it's really bothering me because it's affecting the whole event I was planning on doing, last month I bought around 3 nitros with no issues, does anyone know how to fix this?