Hello @MDCB

ok, you made me curious, so I've setup a Helium account and was able to join with a COMX.LoRaWAN868 module using a couple of AT commands. Unfortunately the COMX.LoRaWAN868 module has a different AT command set than the Atom DTU LoRaWAN base so the AT commands I used won't help you much. Also the COMX.LoRaWAN868 module is not covered in UiFlow which means I had to send the AT commands using the UART blocks. Essentially I had to choose LoRaWAN, OTAA, set DevEui, AppEui and AppKey (all three copied verbatim from the Helium Console) and then issue a Join command.

However what I can share is the output of the COMX.LoRaWAN868 module when I switch it over to LoRaWAN mode:

Copyright @2019-2020 Heltec Automation.All rights reserved. AT Rev 1.3 +AutoLPM=0 +LORAWAN=1 +KeepNet=0 +OTAA=1 +Class=A +ADR=1 +IsTxConfirmed=1 +AppPort=2 +DutyCycle=15000 +ConfirmedNbTrials=4 +ChMask=0000000000000000000000FF +DevEui=0123456789012345 +AppEui=0123456789012345 +AppKey=01234567890123450123456789012345

From that I think you might want to try a different class (A instead of C) and a different channel mask (0xFF instead of 1).