Why can I not push a string to an array?

I am currently using mongodb and and I cannot push a string to an array. This is my current code:

 user.OwnedProducts.push(msg2.content)
    user.save().then(() => {
    m3.edit(bot.embed({ description: "Successfully whitelisted the user!" }, message))
    msg2.delete()
})

why will this not work? It does not give me any errors