casting third-party apps (like YouTube, Netflix, etc.) to Apple TV 4K from iPhone

## Goal ## My goal is to cast third-party apps like YouTube or Netflix to my Apple TV 4K. **I do not want to Airplay my screen** but rather control the Third-Party-App via my iPhone. Usually the button looks like this: ## Problem ## If I click on the cast-icon, nothing happens an my Apple-TV is not found. When using Netlfix it tells me, there are no devices found: I tried this with multiple iPhones without any luck. We had a Samsung TV a couple of months ago where everything worked just fine. ## What I already did or tried ## - update my iPhone to newest iOS (17.0.3) - reset my network-settings on my iPhone - update my Apple-TV to the newest tvOS - update the third-party apps to the newest version - call the Apple Support I did everything without any success. ## Network-Setup ##

FRITZ!box 7590 (Mesh Master)
├─ TP-Link Switch TL-SG105 (with IGMP-Snooping)
│  ├─ TP-Link Switch TL-SG105 (with IGMP-Snooping)
│  │  ├─ FRITZ!box 6591 Cable (Mesh Repeater)
│  │  │  ├─ iPhone (wireless)
│  │  │  ├─ Apple TV 4K (wired)
│  │  ├─ FRITZ!box 7490 (Mesh Repeater)
│  │  │  ├─ iPhone (wireless)

The iPhone is two times in the graphic because either way it won't work. FRITZ!box is a router very commonly used in Germany. They are also all updated to the newest FRITZ!OS (the operating system of the FRITZ!boxes). I double-checked, that I am not using a guest-LAN or guest-WLAN. I can also ping the Apple TV from my MacBook seamlessly. The Apple TV can play everything from YouTube or Netflix and has no problems connecting to the internet. AirPlay does also work, but as mentioned is it not my goal to use AirPlay ## What I (think to) know ## On the Netflix support page is a trouble-shoot guide for using the cast-function: > Make sure your Wi-Fi router or modem is set up to allow multicast. For the steps to set up multicast, check the manual that came with your router or contact the manufacturer. To my understanding, multicast is enabled on my FRITZ!boxes so i searched the web and came across IGMP snooping. This is used for multicasting and could allegedly harm in some cases the multicast stream. My understanding is, that IGMP snooping helps the multicasting. I also found out that the Bonjour packages from the Apple TV (Are sent by the Apple TV from my understanding to establish the connection) have a TTL (Time-To-Live) of 1, thus they cannot be routed. To my understanding the mesh-repeaters nor the switches act like a router and don't delete the package. Is there anything in my setup that prevents the usage of those casting features? Any help is appreciated! Thanks in advance! ### Update ### With this configuration:

FRITZ!box 7590 Mesh Master
├─ Apple TV (wireless)
├─ iPhone (wireless)

I got YouTube to work but Netflix still didn't work. Apparently, the 6591 Cable does route the packages or something similar and the package dies. If I got the time, I will try to wireshark into the packages from and to the Apple TV.