Thanks a lot for your response 
Nevertheless, i already did that as it was part of the tutorial mentioned above.
Here is my console :
i also did reset the frame counter ( i mean i just checked the checbox reset frame counter), it started counting at 0 again then i unchecked it , or maybe you mean running this command instead ? :
ttn-lw-cli end-devices set [application-id] [device-id] --session.last-a-f-cnt-down 0
I added those frequencies after having set up the node config though, should i recreate the whole node config and add them during first time configuration ? Does the order also matter ? meaning from lower to higher ?
Thanks a lot 