AIR does not connect

[Out of Gum]

On my (quite old) macbook air with Sierra (10.12) I have AIR 3.04 installed. In the menu bar I have the AIR icon and I see my Devialet 220, which is called 'My Deviatlet-ETH' as it is connected via Ethernet. Via the Qobuz desktop app (I am using the month free trial) I used to be able to stream from my macbook via wifi to the devialet (connected via ethernet). I never used air before as I used airplay but as airplay cannot stream high res I decided to use AIR.

AIR worked for a few days but definitely not flawless as I had to restart AIR and / or Qobuz now and then. However, 2 days ago the connection was lost during play and I could not connect again. Under the AIR icon i can still see the devialet but it is grey and I cannot select it anymore. 'Disable Devialet AIR' is checked. I can still use airplay so the devialet is still connected to the network. Under settings of AIR I can also see an IP address and a MAC address. I have tried to reinstall AIR 3.04 but it still does not work. Under 'Sound' in the preferences menu on the mac I can select Devialet AIR under output but nothing happens. In Qobuz I can also select Devialet AIR I have not done any OS updates or whatever so I do not understand what is going on.

Does anyone have a solution for the above?