Hi
@PARIMI You could try these trouble shooting steps
1.Check that you are running on the latest firmware version 30.12.112.46
2.Make sure to check on your device if you have the setting "turn off hotspot automatically" function set by default to X minutes instead of 'Never'?
You can check by following these steps;
Settings-> Network & Internet -> Hotspot & tethering -> wi-fi hotspot -> turn off hotspot automatically.
3.If that was set already to never, could you back up your data and perform a factory reset and see if this will solve it.
4.If nothing above solved your issue, then I will recommend you to visit your nearest ASUS Service Center.