Hi Sergey,
Bonjour gateway service only helps to discover the device using mDNS packets between two different VLANs.
If you are able to discovery the Apple TV but unable to connect to it then it could be a different issue related to the network.
Try to ping the IP address of the AppleTV from your device and see if it is working fine.
Regards,
Syamantak Omer
Syamantak Omer | Sr.Staff TSE | CWNA | CCNA | RASZA | RICXI