Cloud9: "Invalid host header" on React & nodejs app

Question

Im developping a Reactjs & nodejs webapp on AWS's cloud9. My problem is that i struggle to make a HTTP request from Reactjs frontend to my express backend server. Both back and front run well separately. React run on port 8080 and express on port 8081.

Here is the frontend request:

async function getAccessToken(){

 await axios.get('/api/token',{ 
     keepAlive: true}).then(function(response){ 
   response.json().access_token;
 }).catch(function(error){
 console.log('Error dans App.js: ', error);
     
 });

}

Heres the server :

const secureServer = https.createServer({passphrase:process.env.PASSPHRASE, cert: certfile, key: keyfile,}, app);

secureServer.listen(process.env.PORT_SERVER, console.log('Server started on port', process.env.PORT_SERVER));

When i start both and access the application preview, i get an "Invalid host header". So i searched here, and i dont want to mess with react-scripts webpack.config.js. I tried to set a "proxy": http://0.0.0.0:8081 in react package.json, to no avail.

Im at a loss here and hope someone can help.

Thanks in advance.