Bad Request for Adding Tracks to Playlist

[chrissy314]

Plan

Free

Country

United States

Operating System

Android

My Question or Issue

I'm trying to develop an Android app that allows you to create a playlist and add tracks. I am currently using the Kaaes Spotify Web API wrapper for Android since it seems like the Android SDK does not have this functionality. The Kaaes wrapper uses the old URL for requests, in the format: https://api.spotify.com/v1/users/{user_id}/playlists/{playlist_id}/tracks

I checked out the Spotify blogpost in 2018 that spoke on new, shorter URLS and at the time of the post, the old URLs were supposed to still work. Unfortunately, I keep running into a 400 Bad Request error. I checked my URL against the sample URLs with sample data and they look the same aside from including user ID info. Does anyone know if the old URLs still work or have any recommendations?