change your model value to a lower (public) model

you might be here because the link says that you didn't pass an API key (but you did)
what helped me resolve this issue was changing the model. seems like i didn't have access to the one i tried at first: 

ex: 

//initial 

async function getReply(){

const response = await openai.createChatCompletion({

model: 'gpt-4', 

messages: conversationArray

})

console.log(response)

} 

//updated with lower model value

async function getReply(){

const response = await openai.createChatCompletion({

model: 'gpt-3.5-turbo',

messages: conversationArray

})

console.log(response)

}