I can’t find what permissions are required or what product type to use. I am wanting to use Linkdn API to DM, but can’t find out how.
I believe it will need special permissions.

POST https://api.linkedin.com/v2/messages

My backend (Node js) code is

app.post('/send-messageLink', (req, res) => {
const accessToken = req.body.accessToken;
console.log('214-----------',accessToken)

axios.post(
'https://api.linkedin.com/v2/messages',
{
recipients: [{ "person": "urn:li:ant-sal:b2b7" }],
subject: "Group conversation title",
body: "Hello everyone! This is a message conversation to demo the Message API.",
messageType: "MEMBER_TO_MEMBER",
attachments: ["urn:li:digitalMediaAsset:123ABC"]
},
{
headers: {
  "Authorization": `Bearer ${accessToken}`,
  "Content-Type": "application/json",
  "X-Restli-Protocol-Version": "2.0.0"
}
}
)
.then(response => {
console.log(response.data)
res.status(200).json(response.data);
})
.catch(error => {
console.log(error)
res.status(error.response ? error.response.status : 500).json(error.response ? 
error.response.data : error.message);
});});

Response recieved is

 data: { serviceErrorCode: 100, message: 'Not enough permissions to access: POST /messages', status: 403 }