invisible minimserver

[lyapounov]

We all know that UPnP is a very instable protocol, and that, as an example, the renderer dissappear from Lumin app, but by unloading the app and loading again they all are magically back.

But today, suddenly, and without any change, after many month without this issue, minimserver has totally dissapeared from the radar: no app (even kazoo) sees it, whether is it on my iPad, iPhone or iMac; and the minimwatch icon is grey.

However, login onto my synology, and lauching minimserver (on port 9790) is perfectly fine: minimserver is up and running.

I rebooted my router: no way.

To be clear : I have only one network (192.168.73.x), ohnet is fine.

What shall I do ? I have now no music...

A side question should I tick or not UPnP discovery in the router ?