Please this post to learn about what key to use... It has to be the Posting Private Key as the picture shows:
https://steemit.com/music/@prc/introducing-dsound-a-decentralized-sound-platform-using-steem-and-ipfs
Hope this solves your problem, if not please get to the dsound channel at steemit.chat and ask for help there, me or other fellow users will help you out for sure! :)