I have the same problem. RUTX12 on latest firmware (00.07.00) is connected to 4G but does not use it as internet connection. I've checked that the WWAN interface is dragged to the top as @ErnestasB suggested:
The connection is also of decent quality:
Still I am unable to access any service on the internet. The router will not connect to Teltonika RMS or ping the Google DNS:
However, if I remove the sim card from the router and put it into my phone, it is working. The router has already been rebooted twice. Any ideas on this?
Edit: The troubleshoot-file can be downloaded [removed]. Don't worry about the date. The file is from today, but the time of the router is out of sync.
Edit2: It is now working. Indeed the default APN, although it seemed OK, was incorrect. The problem could be solved by manually configuring the APN given by the carrier.