Rejoin device failing - how to reset?

Hi there

My Elsys ERSC02-devices ( was joined and working on an earlier stage. After been taken of the network for a while, they can´t join. I´ve been told that a possibly explanation is that the devices them selfs already are in a “joined state” and therefore can´t rejoin. I´ve tried to remove and add the devices once again on the application server. I do see the gw receiving the join request. Another option I tried is by adding and configuring by the NFC feature (Elsys app), where both OTAA and ABP options has been tried out. A good hint on how to fix this is appreciated.