Android app doesn't display the connection

Apps & Services Android App
1

Hi
I installed openHab on my Synology NAS via Docker.
When I launch the app on my Android smartphone, I have an error : “no network connection available” whilst it display connected inside the parameters.
Do I have to open specifics port on my NAS or pages in openHab ?

2

Did you enter the NAS as local or remote connection?

3

Local
I do not open the Access from internet

4

How is the Android device connected to the network (wifi, VPN, etc)?
Can you reach the server from the browser on your Android device?

5

Android device is connected on wifi.
I Can reach openHab from this device.
In openHab Android app if I select parameters/openHab server, local is connected and distant not set
However the app display the error: connection to local server failed.