Cannot delete tracks from a playlist using the API. Receiving 401 error.

[kcrb]

Plan

Free/Premium

Country

Canada

My Question or Issue

I've been trying and failing to delete tracks from a playlist using the API. Every method I attempt results in a 401 error from spotify. 

This is a JavaScript Web App and I'm performing both Oauth and delete requests from a Node.js backend. 

I have a valid Oauth2 flow and can create/add tracks to playlists on an authorized account. 

I am using the passport.js Spotify Strategy to secure an access token and I have defined scopes of  'user-read-email',  'user-read-private', 'playlist-modify-public',  'playlist-modify-private',

Here is the code for my route handler in Node/express:

app.get('/api/playlist/update', requireLogin, async (req, res) => {
    // * ----- CONFIG ----- (Spotify access token)
    const config = {
      headers: {
        Accept: 'application/json',
        Authorization: `Bearer ${req.user.accessToken}`,
        'Content-Type': 'application/json',
      },
    };

    // * ----- GET SNAPSHOT ID OF PLAYLIST -----
    const url = `https://api.spotify.com/v1/playlists/${keys.URI_TOP10}`;

    const response = await axios.get(url, config);
    const snapshot_id = response.data.snapshot_id;

    // console.log(snapshot_id);

    // * get tracks
    const responseTracks = await axios.get(
      `https://api.spotify.com/v1/playlists/${keys.URI_TOP10}/tracks`,
      config
    );
    const tracks = responseTracks.data.items;
    const trackURIs = tracks.map((track) => {
      return { uri: track.track.uri };
    });

    // console.log(trackURIs);

    // * ----- FORMATE FETCH REQ BODY -----
    const body = JSON.stringify({
      snapshot_id: snapshot_id,
      tracks: trackURIs,
    });

    // console.log(body);

    // * ----- DELETE PLAYLIST TRACKS -----
    fetch(`https://api.spotify.com/v1/playlists/${keys.URI_TOP10}/tracks`, {
      method: 'DELETE',
      headers: config,
      body: body,
    })
      .then((response) => {
        if (response.ok) {
          console.log(
            `Tracks successfully deleted from playlist with ID ${keys.URI_TOP10}`
          );
        } else {
          console.log(response);
          throw new Error('Error deleting tracks from playlist');
        }
      })
      .catch((error) => {
        console.log(error);
      });
  });

[Ximzend]

Error 401 means: Bad or expired token.