Emby for iOS fails to complete Google Cast connection to Google Home Mini

[Robin5446 0]

The Google Home Mini is discovered correctly in the Emby iOS app. When I select it, the speaker plays the normal Google Cast connection sound, but Emby does not complete the connection:

• No checkmark appears next to the Google Home Mini.
• The active playback device remains the iPhone.
• Playback stays on the iPhone.
• The Google Home Mini never starts playing the audio.

The result is the same whether I select the Cast device before starting playback or while music is already playing.

Environment

• Emby Server 4.9.5.0
• Emby for iOS 2.2.56 with IP 192.168.A.x
• Emby Server running on a Synology NAS with IP  192.168.C.x
• Google Home Mini as Cast receiver with IP 192.168.B.x
• iPhone, Emby server and Google Home Mini are located in separate routed VLANs/subnets

Google Cast from the Qobuz app on the same iPhone to the same Google Home Mini works correctly. This confirms that the iPhone, Google Home Mini, Cast discovery and basic inter-VLAN communication are functional. I captured the traffic on the gateway during an Emby Cast attempt.

The capture shows:

• The iPhone successfully establishes a TCP connection to the Google Home Mini on port 8009.
• The TLS handshake completes successfully.
• Cast application data is exchanged in both directions.
• The Emby server can communicate with the Google Home Mini on ports 8008 and 8009.
• HTTP requests to the Home Mini on port 8008 receive HTTP 200 responses.
• After the Cast attempt, the Home Mini successfully performs DNS queries and connects to Google services via HTTPS/QUIC.

However, I do not see the Google Home Mini subsequently requesting the actual media stream from the Emby server. All relevant local subnets are configured under Emby's LAN Networks setting 192.168.A.0/24 192.168.B.0/24 192.168.C.0/24. The Emby debug log confirms that playback requests are classified as local: isInLocalNetwork: True.

I tested both downloaded/offline content and normal server-side content. With an offline item, I saw a separate error where the iOS app requested an item using an ID such as: local:<item-id> and the server returned: System.FormatException: Unrecognized Guid format HTTP 500. However, I then tested a normal music item that had not been downloaded to the iPhone. In that case:

• Emby used the normal server item ID.
• PlaybackInfo was generated successfully.
• Direct Play, Direct Stream and Transcoding were enabled.
• The request was correctly classified as local.
• No obvious PlaybackInfo or transcoding error occurred.

Despite this, Emby still reported the playback session as running on the iPhone, not on the Google Home Mini. The Home Mini also never appeared as a playback client in the Emby server log and never requested the media stream from the server.

Since casting from Qobuz works correctly on the same iPhone and Home Mini, and the packet capture shows that the initial Cast communication succeeds, this appears to be an issue with the Emby iOS Cast session handling rather than general network connectivity. Can anyone help or confirm?