I purchased a RUTX11 for our camper van. The use cases are simple: connect to external WLAN or LTE (in this priority) to provide access to internet and serve connection using LAN or WLAN.
Probably this is the default usecase for mobile people but even after doing research I had quite some trouble setting up the process and misconfigured the device a few times, while playing with different settings as it was not working as expected, so the IP was not reachable over (W)LAN anymore. To not lose too much time I did some resets and finally I found where I fail.
Setting up an (internal) AP and connecting to an external AP did work quite well, noting too interesting:

I assigned the interface to network wwan as e.g. seen in https://www.youtube.com/watch?v=INGKWNqnZZ0

I also set failover rules:

As I currently removed the SIM card, mob1s1a1 is stopped, that is fine but here I already did not understand why wwan is offline (I think it said offline, the screenshot is from a later test where it says "interface stopped", sorry for the blury image). In the interface section I can also see WWAN as being stopped:

I found some questions like https://community.teltonika-networks.com/48905/rutx11-how-fix-network-interface-status-stopped that sounded like the exact same problem but as I have seen the video 10 times and in the video the interface is just up and running after adding the WLAN connection, it does not help. Also I have the current firmware:

I noticed the following effect when playing around: by some time I connected to my WAN WLAN I used some random name instead of wwan and for some reason the interface switched to active. So I added a SIM card and that was also active, then. To test if that works if WLAN is gone, I deactivated the corresponding interface and had internet over LTE... then I turned the interface back on and it... failed. It just says "stopped". I also did not get a running interface for my WAN WLAN connection any more till now.
Also I checked logs but did not see anything noticable and as I do not really know what to do, I need your help.
As I also failed uploading readable images to this forum, I attached the original images for the moderators...