Am trying to send a request to the server to save a post. Am using Nextjs and everytime i try to send it gives me this Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client.

Here is my code

Post.js
async function uploadPost(post) {

const response = await fetch('/api/savePost', {
  method: 'POST',
  body: post,
});

if(!response.ok) {
  throw new Error('Failed to post')
}

return await response.json();

}

savePost.js

export const config = {
      api: {
      bodyParser: false,
   },
}

export default const post = async (req, res) => {
  if (req.method !== 'POST') {
    return res.status(405).json({
     message: 'Method not allowed'
    })
  }

  // const postData = JSON.parse(req.body);
  const savedPost = await prisma.post.create({
   data: req.body
  });

  res.status(200).json({message: 'Post saved successfully'})
  res.json(savedPost)
 };

Am using Prisma for the db I get this error

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
at new NodeError (node:internal/errors:371:5)
at ServerResponse.setHeader (node:_http_outgoing:576:11)
at NodeNextResponse.setHeader (C:\Users\user\Documents\My Received Files\js\twitter-clone\node_modules\next\dist\server\base-http\node.js:56:19)
at DevServer.renderError (C:\Users\user\Documents\My Received Files\js\twitter-clone\node_modules\next\dist\server\base-server.js:1134:17)
at DevServer.renderError (C:\Users\user\Documents\My Received Files\js\twitter-clone\node_modules\next\dist\server\next-server.js:493:22)
at DevServer.run (C:\Users\user\Documents\My Received Files\js\twitter-clone\node_modules\next\dist\server\dev\next-dev-server.js:452:35)
at async DevServer.handleRequest (C:\Users\user\Documents\My Received Files\js\twitter-clone\node_modules\next\dist\server\base-server.js:307:20) {
 code: 'ERR_HTTP_HEADERS_SENT'
}
error - uncaughtException: Error [ERR_STREAM_WRITE_AFTER_END]: write after end