Notion API, Getting Invalid_Grant when trying to generate authorization token

I created an intergration on Notion.so

I got the interim OAuth code using the following URL Add to Notion

This above URL, after authorizing from Notion UI, gives me the following code XXXXXXX-XXXXXXX NOW using the code from above step to get the authorization code

POST https://api.notion.com/v1/oauth/token HTTP/1.1
Authorization: Basic XXXXXXXOnNlY3JldF9DeXp0d1A0TVNLZkZIY0XXXXXXXXX
Content-Type: application/json
Content-Length: 164

{
    "grant_type": "authorization_code",
    "code": "XXXXXX-XXXXX",
    "redirect_uri": "http://localhost:8080/api/notion/auth/callback"
}

This Response in

{
  "error": "invalid_grant"
}

What am I missing?

Thanks In advance!

Try removing the redirect URL from both calls to get the access code and the authorization token. This returned a success response from the server when I tried this.

app.get(auth_path, (req, res) => {
  res.redirect(
    //Documentation expects "${api_url}/v1/oauth/authorize?client_id=${process.env.NOTION_ID}&response_type=code&redirect_uri=${redirect_uri}"
    encodeURI(`${api_url}/v1/oauth/authorize?client_id=${process.env.NOTION_ID}&response_type=code`),
  );
});

`enter code here`app.get(access_token_path, ({query: {code}}, res) => {
  //Exchange authorization code for access token
  axios({
    method:"post",
    url:"https://api.notion.com/v1/oauth/token", 
    data: {
    "code":code,
    "grant_type": "authorization_code",
    
    }, 
    headers: {
    "Authorization": `Basic ${auth_token}`,
    "Content-Type": "application/json"
    }
  }).then((response) => {
    res.sendStatus(200)
  }).catch((err => {
    console.log(err)
    res.sendStatus(500)
  }))
});