AirCard 785 is logging out IoT Devices after 24h

I have a AirCard 785 which i want to use as a IoT Devices Hotspot. When i set it up with my datacard it works perfectly fine for 24 hours. After this, the Hotspot is still active, but the devices cannot access it anymore.

When i connect with my mobile phone after 24 hours to the device, instead of giving me Internet access, it auto-routes to the aircard-configuration website hosted on the router. when i enter my password there, i am free to use the internet.  It works without this forced rerouting directly after a reboot.

I guess this forced sending of the aircard-config page prevents the IoT Devices from accessing the IPs they need to access. 

Is there any way to prevent this behaviour and use this Aircard Router as a long-term Hotspot? 

It's this Router: https://www.netgear.de/home/products/mobile-broadband/hotspots/AC785.aspx