Roon ARC not connecting to 4g

I have a Draytek Vigor 120 in bridge mode
I have a Synology RT2600ac with upnp enabled
the core is running on an intel nuc


The port forwarding is correct and the Roon application says ARC is working but when I connect via 4g it won’t connect.

The Broadband is Plusnet fibre

also its a static IP

4 posts were merged into an existing topic: Issue with Roon ARC connection on Synology RT2600ac with Draytek Vigor 120 in bridge mode (ref#OOBSSC)