OTAA Network Mode

Issue: ERROR:99

Setup:

Server:

Details:
The documentation for the RAK7201 seems to suggest that the device supports Network Access Mode OTAA. Unfortunately, when I try to configure OTAA mode the device fails to connect with ERROR:99 displayed via the terminal interface. ABP Mode works fine.

In the TTN live data for this device I can see the Accept Joint-Request & Forward Joint-Request Message messages, but my device fails to join.

I’m using AU915 FB2 and are trying to connect to the TTN application server.

My device is running the latest firmware that i could find: “V1.0.2.210520_Release”.

Can you please confirm whether the RAK7201 supports OTAA using AU915 FB2 and if so provide some trouble shooting advice?

Kind Regards
Greg