You probably don't have access. I'm not sure what the exact access requirements are - I think you either have to be a GPT Plus subscriber, have contributed code to an OpenAI repo on github, or be on one of their lists of researchers.
Try gpt-3.5-turbo-0301 - I think everyone has access to that.
"During the gradual rollout of GPT-4, we’re prioritizing API access to developers that contribute exceptional model evaluations to OpenAI Evals to learn how we can improve the model for everyone."
FWIW, I'm a GPT Plus subscriber and haven't been given API access to GPT-4 despite being on the waiting list for as long as it's been up. I'm told that submitting evaluations can move you up in the queue, but I haven't tried that.
Try gpt-3.5-turbo-0301 - I think everyone has access to that.