CORS Error When Sending POST Request from Client to Express Server

I am getting a CORS error when trying to submit a form from my website to my Express server. Here is the setup and the problem:

Server (Express) Code:

const express = require("express");
const cors = require("cors");

const app = express();
app.use(cors({
  origin: 'https://www.teckwithfeya.com'
}));
app.use(express.json());

app.post("/send", (req, res) => {
  console.log(req.body); // Log the received data
  res.send("Form submitted successfully");
});

app.listen(7000, () => {
  console.log("Server is running on port 7000");
});

Client-side JavaScript:

document.addEventListener("DOMContentLoaded", function () {
  const contactForm = document.getElementById("contactForm");
  contactForm.addEventListener("submit", function (event) {
    event.preventDefault();

    const formData = new FormData(contactForm);
    fetch("https://www.teckwithfeya.com/send", {
      method: "POST",
      body: formData
    })
    .then(response => response.text())
    .then(data => {
      console.log(data);
    })
    .catch(error => {
      console.error("Error:", error);
    });
  });
});

When I submit the form, I get the following CORS error in the browser console:

Access to fetch at ‘https://www.teckwithfeya.com/send’ from origin ‘https://www.teckwithfeya.com’ has been blocked by CORS policy: Response to preflight request doesn’t pass access control check: No ‘Access-Control-Allow-Origin’ header is present on the requested resource.

I have set up CORS on my Express server with cors middleware.
I tried using both fetch with JSON and FormData.