My MacBook Pro and iPad will not pick up the Air Play or the Home sharing on my AppleTV which was working yesterday

I was previously able to use my AppleTV with airplay and iTunes home sharing to my 2 macbook pros and my iPad. However, it has suddenly stopped connecting to both airplay and home sharing, even though both are turned on and the correct itunes account has been logged into on all devices. We have reset AppleTV but that has not resolved the issue. There is no airplay icon on any of the macbooks or iPad. Has anyone else experienced this and found any solutions? Thanks.