Fire TV Stick 4K Select (Vega OS) — FCast receiver binds only to internal 172.17.0.x IP; port 46899 not listening on real Wi-Fi IP

[66cam99]

What happened?

What happened?
The FCast receiver (version 1.0.0) on a new Fire TV Stick 4K Select (Software Version: OS 1.1 (1401010010120); Fire TV Home Version: 1.72.0.176896.0) only displays and binds to the internal/virtual IP 172.17.0.4 on port 46899. The device's actual DHCP IP is 192.168.0.35.

• Ping to 192.168.0.35 succeeds from other devices on the network.
• Port scan (Test-NetConnection 192.168.0.35 -Port 46899) fails with TcpTestSucceeded: False (the port is not listening on the real Wi-Fi interface).
• Fire TV Stick has a system notification "FCast Receiver Network Listener Service - Listening on port 46899 (TCP)", but the port remains unreachable.

Grayjay discovers the receiver via mDNS (shown as [Amazon-AFTCA002] for QR scan and [FireTVStick] for manual entry) and displays: "Connecting to [Amazon-AFTCA002] (or [FireTVStick]). Make sure you are on the same network. VPNs and guest networks can cause issues." As a result, neither QR code scanning, mDNS auto-discovery, nor manual IP entry works. Fcast app stays stuck on "Waiting for a connection" and the receiver never shows any incoming attempt.

What did you expect to happen?
The receiver should bind to the real Wi-Fi interface (0.0.0.0 or 192.168.0.35:46899) so that devices on the same home network (192.168.0.x) can successfully cast using manual entry, QR code, or mDNS.

Replication steps

1. Open the FCast receiver app on the Fire TV Stick 4K Select (it shows 172.17.0.4 : 46899).
2. On Android phone, open Grayjay (ver. 372) and que video for playing.
3. Tap the casting button.
4. Attempt QR scan with Android phone from Grayjay app
5. Grayjay shows a continuous progress spinner and the message "Connecting to [Amazon-AFTCA002]"
6. Attempt manual connection with IP 192.168.0.35 and port 46899.
7. Gray shows continuous progress spinner and the message "Connecting to [FireTVStick]"

Which sender are you using?

Grayjay

FCast Receiver Version

1.0.0

Grayjay Version

372

Which operating system are you using on your receiver?

AndroidTV

Which protocol did you use to cast?

FCast

What plugins are you seeing the problem on?

No response

Plugin Version

not applicable

When do you experience the issue?

• While logged in
• While logged out
• N/A

Are you using a VPN?

No

Relevant log output

Unable to provide FCast receiver logs because the app is running on an Amazon Fire TV Stick 4K Select (Vega OS), where logs are not accessible to the user.

For reference, this device replaced a 2020 Amazon Fire TV Stick (running classic Fire OS) that previously worked with FCast casting from the same mobile device.