Cant manage to use anynmous authorization for fetching images in an album (android/java)

[User]

Hello. I want to fetch images in an imgur album. I know the id of the album. For now my code should just print the json, but the app crashes.

here is my code (I'm doing the call from an async task): http://pastebin.com/af5Ju7z1

And this is the stacktrace

Error
java.io.FileNotFoundException: https://api.imgur.com/3/gallery/album/bRpHL
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:238)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java)
at com.dcs.memebrowser.tasks.ImgurAsyncTask.doInBackground(ImgurAsyncTask.java:64)
at com.dcs.memebrowser.tasks.ImgurAsyncTask.doInBackground(ImgurAsyncTask.java:20)
at android.os.AsyncTask$2.call(AsyncTask.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)