The ChatGPT Paid plan and the OpenAI API plan are two different things. You must have sufficient tokens in your API account to use it with our app. If you have not connected your credit card, it will show you like this:

Go to this URL and check if you added a credit card to your account

You need to have an OpenAI Paid Plan, you can create OpenAI paid plan here:

You can find your OpenAI credit Usage limit here: