Unable to acces a third party API (Shapeways)

Hello,

I’m trying to connect my Wix web site with Shapeways API:
https://developers.shapeways.com/quick-start#make-your-first-request
The begging is going pretty well.
I can access my token with the following code:

import { fetch } from ‘wix-fetch’;

export function accessShapeWays() {
let url = " https://api.shapeways.com/oauth2/token ";
let hdrs = {
“Content-Type”: “application/x-www-form-urlencoded”
};
let info = “grant_type=client_credentials&client_id&client_secret=”;

return fetch(url, {
method: “post”,
headers: hdrs,
body: info
})
.then(response => response.json())
.then((json) => {
return json.access_token;
})
. catch ((err) => { console.log(err) });
}

Then I try to “make an API test request” (following the guide) which doesn’t work with the following code that I added after the one above :

export function testRequest() {
// -----------------------------------------------------------
let tokenFinal;
accessShapeWays()
.then((acces_token) => {
let api_url = " https://api.shapeways.com/materials/v1 ";
let hdrMat = {
“Content-Type”: “application/json”,
“Authorization”: “Bearer” + “\xa0” + acces_token // the error probably comes from this line or the one above
// seen on https://www.wix.com/corvid/forum/community-discussion/using-a-third-party-api-with-wix-fetch
};
console.log(hdrMat);
fetch(api_url, {
method: “get”,
headers: hdrMat
})
.then(response => response.json())
.then(json => console.log(json))
. catch ((err) => { console.log(err) });
});
}

The error message I get is : “[{“result”:“failure”,“reason”:“Authentication Error”}]”
I’ve looked into all the documentation and examples I could find from Wix and Shapeways, but nothing seems to work.
I think that the problem comes from the line : “Authorization”: “Bearer” + “\xa0” + acces_token
I also tryed : “Authorization”: "Bearer " + acces_token but it’s not working eather.

Does someone know what could be the solution ?