It looks to me that this is a “catch all” error that can mean several different failure modes, each with a different solution. I say this because I’ve encountered that already.
Caveat: problem with below list is that a cause I propose CAN NOT cause a join problem, but it happen to me by sheer coincidence so I think it does. Thus, I welcome more experienced members to critique and dispute entries - it’s really helpful to me, personally.
- Firmware bugs - updating firmware and, in one case, flashing same version solved issue (??)
- Hard-cycling sensor by removing batteries; just resetting via OTAA didn’t “take”
- Purchasing used sensor, with new AppKey correctly programmed, it didn’t want to join until reflashed firmware. This happened to me and also @Chouffi, above.
- Placing sensors physically too close gateway - that bit me on first week I was experimenting with LG191 & qty 8 RS191 sensors. I wasted easily 20 hours scouring my software configuration, when problem was physical. Solved accidentally by taking sensor with me to the car - it transmitted 100% reliably from my car in the parking lot
Didn’t happen to me (yet), but these appear to be other causes that manifest same way:
- programing wrong spreading factor.
- disagreement between channels setting in sensor vs gateway, so it sees join request but fails on JoinAccept
- accidentally programming sensor for wrong region may do this. Also HERE.
- software anomalies on gateway
That’s all I know.