Help, kindle PW5 lock me out of USBNetlite

[pw5]

I installed USBNetlite 1.0M as it support armhf, which my 5.17.1 kindle would happily run, and SSH works for few days, i left my pw5 for like months without connect SSH and im hit with Wrong password for ssh root@192.168.15.244
and after type dropbear in Kterm (i install it in case SSH dead when i just new to jailbreak), it shows :
/mnt/us/usbnetlite/etc/dropbear/dropbear_rsa_host_key not found
C:\Users\FL>ssh root@192.168.15.244
root@192.168.15.244's password: Permission denied, please try again. root@192.168.15.244's password: Permission denied, please try again. root@192.168.15.244's password: root@192.168.15.244: Permission denied (publickey,password).

the password "kindle" works normally but now it didnt, i tried delete USBNetlite and reinstall but no luck