Getting 404 errors when attempting to access a user's playlists

I’m using Node version 5.5.0, and spotify-web-api-node version 2.3.0. I’m using the following function to get the playlists from my own Spotify account.

var SpotifyWebApi = require('spotify-web-api-node');
var clientId = '<client id>';
var clientSecret = '<client secret>';

var spotifyApi = new SpotifyWebApi({
    clientId: clientId,
    clientSecret: clientSecret
});

function getUserPlaylists(userId) {
    spotifyApi.clientCredentialsGrant()
        .then(function(data) {
            spotifyApi.setAccessToken(data.body['access_token']);
            spotifyApi.getUserPlaylists(userId)
                .then(function(data) {
                    console.log(data);
                }, function(err) {
                    console.log('Something went wrong!', err);
                });
        }, function(err) {
            console.log('Something went wrong when retrieving an access token', err);
        });
}

However, whenever I call this function with my own Spotify user ID (I signed up with Facebook), I get the following error: Something went wrong! { [WebapiError: Not found.] name: 'WebapiError', message: 'Not found.', statusCode: 404 }. Other API functions work still, but all of a sudden this one ceased to work even though I haven’t touched my server or the code for my server since it was working well. I checked the endpoints in the spotify-web-api-node source code and they seem to still be correct for getUserPlaylists.

[stfnlzvn]

Ran into the same problem when using getPlaylistTracks(). Fixed it by passing playlist.owner.id rather than user.id

[jswny]

Once again, after having changed absolutely nothing on my production server, I’m getting the same error again. Testing my site on my local machine yields the same results. Upon further investigation, I’ve found the problem. After I grab the user’s playlists, I’m iterating over them like this:

spotifyApi.getUserPlaylists(userId)
    .then(function(data) {
        var playlists = data.body.items
        var playlistsArr = new Array()
        var count = 0
        playlists.forEach(function(playlist) {
            spotifyApi.getPlaylist(userId, playlist.id)
                .then(function(data) {
                    playlistsArr.push({
                        name: playlist.name,
                        id: playlist.id,
                        img: playlist.images[2].url,
                        followers: data.body.followers.total,
                        total_tracks: playlist.tracks.total
                    })
                    if (count == playlists.length - 1) {
                        callback(playlistsArr)
                    }
                    count++
                }, function(err) {
                    console.log('Something went wrong retrieving an individual playlist!', err)
                })
        })
    }, function(err) {
        console.log("Something went wrong retrieving the user's playlists!", err)
    })

However, the page would hang and never load, which was the reason I started noticing this problem. Turns out, some of the Spotify playlists that I followed were made public on my profile, thus they were pulled into what my code thought was an array of my playlists. Then, when I tried to use getPlaylist(userId, playlist.id) it would hang. That’s because those other playlists that I had followed were not mine, so when I looped through one of those, the whole script would hang. To fix this, I’ve made all of those secret but you could just as easily check each playlist for the property collaborative or something similar before looping through each one. That would explain the 404 errors as well because the API was trying to access a playlist that didn’t exist from my user ID. This turned out to be my incompetence, nothing wrong with any of the tools I was using. Hopefully this helps others to fix this mistake more easily. Thank you @JMPerez for the help.