GPT-3.5-turbo does not work for me

API
1 
console.log("OpenAI script started on this page");
chrome.runtime.sendMessage({ type: "injectScript" });

chrome.storage.local.get("openaiApiKey", function (result) {
  var apiKey = result.openaiApiKey;
  if (apiKey == null) {
    apiKey = prompt("Please enter your OpenAI API key:");
    chrome.storage.local.set({ "openaiApiKey": apiKey });
  }

  document.addEventListener("keydown", function (event) {
     if (event.ctrlKey && event.shiftKey && event.keyCode === 75) {
      const activeElement = document.activeElement;
      const isContentEditable = activeElement.isContentEditable;
      const isInputField = activeElement instanceof HTMLInputElement || activeElement instanceof HTMLTextAreaElement;
      const textValue = isContentEditable ? activeElement.textContent : activeElement.value;
      if (textValue.includes("::")) {
        const promptText = textValue.substring(textValue.indexOf("::") + 2).trim();
        const apiURL = "https://api.openai.com/v1/engines/gpt-3.5-turbo";
        const headers = {
          "Content-Type": "application/json",
          Authorization: "Bearer " + apiKey,
        };
        const data = {
          prompt: promptText,
          max_tokens: 128,
          temperature: 0.7,
        };
        console.log("Detected keyboard combo");
        console.log("Sending API request with prompt:", promptText);
        fetch(apiURL, {
          method: "POST",
          headers: headers,
          body: JSON.stringify(data),
        })
          .then((response) => response.json())
          .then((data) => {
            const generatedText = data.choices[0].text.trim();
            const newTextValue = textValue.replace("::" + promptText, generatedText);
            if (isContentEditable) {
              activeElement.textContent = newTextValue;
            } else {
              activeElement.value = newTextValue;
              activeElement.dispatchEvent(new Event("input", { bubbles: true }));
            }
            console.log("API response received:", generatedText);
          })
          .catch((error) => console.log(error));
      }
    }
  });
});

chrome.runtime.onMessage.addListener(function (request, sender, sendResponse) {
  if (request.type === "injectScript") {
    chrome.tabs.executeScript({
      file: "content.js",
    });
  }
});

I am getting the following error

POST https://api.openai.com/v1/engines/gpt-3.5-turbo 405
(anonymous) @ content.js:31

I have no idea what I am doing wrong, checked it multiple times, also ran the code through ChatGPT to find an issue with it, it could not find an issue other than

  1. checking API key is valid
  2. endpoint is valid.

which both should be correct ( API key works on other models)
Endpoint is correct as well as far as I am aware