Adding Static route to a custom app (plex) doesn't seems to work

I need to add a static route to an app.

The app is plex Docker, installed as custom app exposed with a static ip.

I need to add the static route to comply with multicast routing according to this guide : Manual:Multicast detailed example - MikroTik Wiki

Even if I add the static route from the GUI, plex dlna is not routed to the other lan.

Network configuration is fine, other dlna server is properly routed.

Am I missing something ? Or static routing is not working ?

Actually I don’t even know how to check if the route has been properly created.