Home sharing signal lost to Apple TV

Hope someone can help. I've had apple TV for several years (generation 2). Running latest software through an iMac. I can watch apple tv for several hours without fault, then in the space of 30 minutes the home sharing signal is lost momentarily 2 or 3 times and an apple tv message appears instructing me to turn on home sharing. At the iMac, home sharing is on with correct apple id. Only way I can reset apple tv home sharing signal is to restart iTunes.

Thanks for that, seems to have worked. Been about six months since I've rebooted the router.

Cheers