Encountering 'model not found' error while trying to use GPT-4 with the OpenAI API

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1

I am attempting to interact with the OpenAI API, but I’m facing issues specifically related to GPT-4. While my code executes perfectly with the gpt-3.5-turbo model, I encounter problems when I attempt to implement the GPT-4 models.

$input_text = "Can you tell me about dogs?";

// Set up cURL for making a request to OpenAI
$curl_instance = curl_init();

curl_setopt($curl_instance, CURLOPT_URL, 'https://api.openai.com/v1/chat/completions');
curl_setopt($curl_instance, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl_instance, CURLOPT_POST, true);

$request_headers = array();
$request_headers[] = 'Content-Type: application/json';
$request_headers[] = 'Authorization: Bearer [YOUR-API-KEY]';
curl_setopt($curl_instance, CURLOPT_HTTPHEADER, $request_headers);

$request_payload = json_encode(array(
    'model' => 'gpt-4',
    'messages' => array(
        array('role' => 'system', 'content' => 'You are a knowledgeable assistant'),
        array('role' => 'user', 'content' => $input_text)
    )
));

curl_setopt($curl_instance, CURLOPT_POSTFIELDS, $request_payload);

$response_data = curl_exec($curl_instance);
echo $response_data . "<br>";

if (curl_errno($curl_instance)) {
    echo 'cURL Error: ' . curl_error($curl_instance) . "<br>";
} else {
    echo "Successfully completed the request<br>";
    echo "Response content:<br>";
    print_r(json_decode($response_data, true));
}

curl_close($curl_instance);

$parsed_response = json_decode($response_data, true);
$generated_output = $parsed_response['choices'][0]['message']['content'];

echo "AI Output: " . $generated_output . "<br>";

When I try to use the gpt-4 model, the following error message appears:

Processing input: what will the weather be like in Newcastle?
{
  "error": {
    "message": "The model: `gpt-4` does not exist",
    "type": "invalid_request_error",
    "param": null,
    "code": "model_not_found"
  }
}

I have also tried using gpt-4-0613 and encountered the same issue. The models based on gpt-3.5-turbo seem to work without any issues. What could be the reason for this?

2

That error’s definitely a permissions issue, not your code. OpenAI switched to a tiered system - you need Tier 1 status for GPT-4, which means making at least one payment first. Here’s what tripped me up: even after paying, there’s sometimes a delay before the models unlock. Check your account limits page in the dashboard - it’ll show exactly which models you can use. Since your code works with GPT-3.5, you’re all set once the account upgrade kicks in.

3

Same thing happened to me. OpenAI changed their access model - you need to be a Tier 1 user now, which means spending at least $5 first. Once you hit that, GPT-4 models unlock. Check your usage tier in account settings. If you’re still Tier 0, that’s why you’re getting the model_not_found error.

4

Had the same exact problem when I started with GPT-4. It’s not your code - it’s OpenAI’s access restrictions. They gate GPT-4 behind usage requirements, so you need payment history before these models unlock. After your first payment, there’s usually a wait before GPT-4 shows up. Took about two weeks for me after I paid. Your PHP code’s fine since it works with gpt-3.5-turbo - this is just account provisioning. Check the playground too - if GPT-4 isn’t there, the API won’t work either.

5

This is an account tier problem. GPT-4 isn’t available on standard OpenAI accounts - you need to make at least one payment first. Even after that, you’ll hit usage limits based on your account history and payment tier. I had the same issue a few months ago and had to wait for my first billing cycle to finish before GPT-4 appeared. Check your model access in the models endpoint or account dashboard. The error message is pretty clear about availability, so it’s definitely permissions, not your code.

6

you might not have access to gpt-4 yet. openai usually requires special permission for that model. check your account settings or hit up support. gpt-3.5 works fine without that, but gpt-4 needs some extra steps.