Hardware-wise, do you have an antenna attached to the “cellular” uFL connector? You’ll never connect without an antenna.
But.. these LTE boards are just more finicky than 2G, so…
You’re using the example from ModularSensors, right? https://github.com/EnviroDIY/ModularSensors/tree/master/examples/logging_to_MMW That example should work with the LTE adapter as written; just change the APN. I usually use “hologram” as the APN, but I think that “apn.konekt.io” works too.
Have you ever connected this XBee3 or SIM card to the internet before. Occasionally with a new sim card or new module or new location it can take a very, very long time (>20 minutes!) for the module to register. I think Shannon’s been getting most of the new cards to connect within the two minutes the program waits, but I know last week she had a long argument with a few SIMs that took hours of fiddling before registering.
What versions of ModularSensors and TinyGSM do you have installed? If you’re not running ModularSensors 0.26.16 and TinyGSM 0.9.19, then you should update.
What output are you getting? Can you paste it in? Are you using PlatformIO or the Arduino IDE? If you’re using PlatformIO, can you add these flags to your platformio.ini flag to turn on some extra debugging printouts and then share the log: (It might be very long.)
If you can’t get the XBee3 to connect in transparent mode, try switching to bypass. Both Shannon and I have seen it suddenly connect when it’s put into bypass. https://www.envirodiy.org/topic/trouble-registering-with-lte-m-network-on-hologram/ All you have to do to change that example to use bypass instead of transparent is replace the text “DigiXBeeCellularTransparent” in lines 101, 106, and 111 with “DigiXBeeLTEBypass” The library will take care of changing the modes for you. Digi warns all over in their literature that bypass mode is deprecated, but my experience has been that it connects to the network much faster and more consistently when using bypass. I do get occasional freeze ups when using bypass mode that lock everything up until the watchdog reset kicks in (~15 minutes), so once you get it to connect to the network you may want to switch back to transparent for a long term deployment. @Aufdenkampe, NeilH and I have some discussion of the different modes here: https://github.com/EnviroDIY/ModularSensors/issues/277