SSH permission denied

Cannot connect to root@192.168.2.2, How can I do?

root@192.168.2.2: Permission denied (publickey).

Which FW are you using?

do you have the UART console?
If yes, you can type the following command to erase the userapp partition:

R.13.3.1

exars@exars-PC-NS700RAR-E3:~$ minicom /dev/ttyUSB0
minicom: /dev/tty8 Unable to open: No permission

why is minicom talking about /dev/tty8?

Another option is to downgrade to R12 and using swiflash to reset the partition: