Roon ARC, AT&T, Nokia BGW320-505, Orbi RBRE 960

Roon Core Machine

Intel NUC 11 Pro NUC11TNHi7 Barebone System - Ultra Compact - 1 x Processor Support Core i7 11th Gen i7-1165G7 Quad-core (4 Core), 8 GB Ram, OS 1.0, Roon Server Software 2.0

Networking Gear & Setup Details

ISP is AT&T Fiber. Router is a Nokia BGW320-505. The NUC is plugged into the main ORBI Router, we have a whole home mesh system.

Connected Audio Devices

Currently only streaming to various PCs and a Sonos Play:5 system.

Number of Tracks in Library

278

Description of Issue

Hello,
I am having difficulty setting up ARC with my internet setup. We have ATT, and the main router feeds an ORBI system. If I plug the NUC directly into the BGW320-505, I am able to get ARC to work. But, since all of the devices I want Roon to stream to are connected to the Orbi system, they no longer show up as available devices. I have gone through in detail this post:
(Arc port-forwarding solution: ATT BGW320 and Asus AX-88U) and have followed the instructions as close as I can(even though I’m using the ORBI and not the Asus). Port Forwarding looks good, but I’m still not having any luck. Is it safe to post my error message from the Roon ARC screen? I’ve seen some people comment that there were certain lines where someone could steal your IP, I guess I’m showing my cards as to how technically inept I am, and it’s no wonder I’m stuck!

Thank you for your help.