is_active false and error 404 not found

[gdnet]

When I try to control the Spotify App from another App, the Spotify App goes inactive as soon as I switch to another App.
Play command gets rejected with error 404 - not found.

LOG 2024-04-15T10:47:09.405Z getDevices 
LOG devices: [{"id":"911...............be2412","is_active":true,"is_private_session":false,"is_restricted":false,"name":"iPhone","supports_volume":false,"type":"Smartphone","volume_percent":100}]

LOG 2024-04-15T10:48:00.374Z url https://api.spotify.com/v1/me/player/play?device_id=911...............be2412
LOG 2024-04-15T10:48:00.374Z axios data {"error": {"message": "Not found.", "status": 404}}

Indeed the getDevices is now empty

LOG 2024-04-15T10:48:00.538Z devices: []

How can you keep the Spotify app in active state ?