Linn Klimaks DSM falls out as audio device after a short period

[Ole_Petter_Drangshol (Ole Petter)]

Roon Core Machine

Roon Core running on QNAP TS251+ with 4 GB RAM. Latest OS version.
When I set up Roon Core it found Klimaks DSM as Roon tested device.
It has run smoothely for a period, but now Core looses contact with Linn Klimax DSM after about 5-10 minutes. A restart of Linn reestablishes the contact.

If I alternatively run from Minimserver on the same QNAP server, the connection is stable.
So now I wonder if there is something i should check in the network for given ports etc that must be opened.
I use among others iPad as controller.
If I go to settings/Audio, the Linn Klimaks DSM is not listed under Roon tested. But I can access it as a Airplay device. However, I guess this gives lower quality signals?
The Klimaks reappears as a Roon tested device after a restart of the streamer.

Networking Gear & Setup Details

ASUS RT-AC87U with latest firmware.
Everything is cabled connections.

Connected Audio Devices

Linn Klimaks DSM (2016 model with latest firmware)

Number of Tracks in Library

28.0000 tracks in my music library

Description of Issue

When I set up Roon Core it found Klimaks DSM as Roon tested device.
It has run smoothely for a period, but now Core looses contact with Linn Klimax DSM after about 5-10 minutes. A restart of Linn reestablishes the contact.

[wklie (Peter Lie)]

In the Asus router web configuration, enable multicast routing in LAN → IPTV.

[Ole_Petter_Drangshol (Ole Petter)]

Thanks for answer. I’m not sure if my model has exactly the setting you are pointing to.
Would this setting do the job?

[wklie (Peter Lie)]

Yes, let’s try these settings and see if they work for you.

[Ole_Petter_Drangshol (Ole Petter)]

Seems to do the trick. The streamer has been stable connected since this change in the router setup was implemented. Thanks for help