First of all, even if it's new I would recommend resetting it fully to its default factory settings, just to make sure everything is fine.
After that I would suggest updating it to the latest available firmware, as you don't have an internet connection - you can do it locally with a file:
Next, if after all these steps you're still out of luck, please insert your SIM, wait for it to register to your operator, and check if on the Overview page you can see that the Data connection is established and is counting the time since successful connection, if not - try setting up Custom APN in Network > Mobile configuration and see if that helps.
If you're still out of luck - head over to Network > WAN and select your wanted main interface as a MAIN, and let's say anything else as secondary. On the right side, you should see something like "IP Address", which should indicate if you have some kind of connection between two ends.
If mobile is still down and not running - please follow these options:
- Are both antennas screwed in tightly and both antennas are for Mobile purposes?
- Do you have any other operator SIM card you could try? (don't forget to give it Custom APN too).
- Is your device compatible with the operator? https://teltonika-networks.com/lt/product/rut240/#ordering
- If after these steps you're still in trouble - send me your troubleshoot file via private message (System > Administration, Troubleshoot tab)
You were also talking about Wired WAN not giving you internet:
- Make sure you have selected Wired WAN as your main interface in the Network > WAN page.
- Make sure you have different subnets between two routers, if you're connecting that Wired WAN cable from other router LAN - that router shouldn't interfere with the RUT240 subnet, so make sure they're different.
- Check if there's anything like a firewall blocking you. On both ends.
Hope this was somehow helpful to you.