I am trying to make a gpt3 chatbot but I keep getting this error on Discord.js v11.

[Uncaught RangeError [MESSAGE_CONTENT_TYPE]: Message content must be a non-empty string.]

client.on("messageCreate", function (message) {
    if (message.author.bot) return;
    prompt += `You: ${String(message.content)}\n`;
    (async () => {
        const gptResponse = await openai.complete({
            engine: 'davinci',
            prompt: prompt,
            maxTokens: 60,
            temperature: 0.3,
            topP: 0.3,
            presencePenalty: 0,
            frequencyPenalty: 0.5,
            bestOf: 1,
            n: 1,
            stream: false,
            stop: ['\n', '\n\n']
        });
        message.reply(String(gptResponse.data.choices[0].text.substring(5)));
        prompt += `${gptResponse.data.choices[0].text}\n`;
    })();
 });            

client.login(process.env.BOT_TOKEN);