I struggled with this issue for months. Both the remote app and iTunes had updated and at some point afterward I realized I could no longer connect to my iTunes Library using Homesharing. After much searching and troubleshooting iTunes and the Remote app, I looked into potential network issues. I have Verizon Fios, with which is supplied a Actiontec router. For me, the issue was solved when I disabled IGMP Proxy within the Advanced settings for the router. This change to the router setting yielded instant results.