can not login to 6860

[wxlwinner]

after I use command "dhcpv6-server restart" to start dhcpv6,the 6860 will reboot continuous,

dhcpv6-server restart continually, when boot, can not login to the 6860. the serial port log is the following,
1. how to resume the system?
2 .how to do the factory reset when can not login the 6860
Thanks a lot.
serial port log:
0S6860 login:
Fri Mar 8 07:21:12 : ChassisSupervisor fpgaMgr info message:
+++ PS 1 present
Alcatel-Lucent Enterprise OS6860-48 8.4.1.141.R03 GA, December 07, 2017.
admin
Password:
Fri Mar 8 07:21:35 : ipsec key info message:
+++ IPsec master security key not set

Fri Mar 8 07:21:49 : ChassisSupervisor appMgr alert message:
+++ appMgrClientTerminated: restarting task
+++ Failed App /bin/dhcpv6srv
+++ Task /bin/dhcpv6srv vrf () restart failed or restart count exceeded - board restarting
+++ Failed App /bin/dhcpv6srv

Fri Mar 8 07:21:49 : ChassisSupervisor bootMgr info message:
+++ Reboot postponed pending PMD completion

Fri Mar 8 07:21:50 : AAA Switch-Warning warning message:
+++ WARNING! Switch Access Vulnerability.
+++ WARNING! Admin user authentication using default password.

Fri Mar 8 07:21:52 : ChassisSupervisor appMgr alarm message:
+++ Aborting PMD for pid 3276: no new PMDs allowed when pending reboot

Fri Mar 8 07:22:01 : PMD main alert message:
+++ PMD generated at /flash/pmd/pmd-dhcpv6srv-03.08.2019-07.21.52

Fri Mar 8 07:22:19 : ChassisSupervisor bootMgr info message:
+++ bootMgrStateMachine: PMD timeout - proceeding with reboot
2019 Fri Mar 08 07:22:35.216115 :: --- REBOOTING ---

--- 2019 Fri Mar 08 07:22:37.654222 :: reboot shutdown complete - rebooting ---

[silvio]

With usb rescue you can rescue your switch (hope you have a backup of the config). You will find infos about rescue in SW-Guide, in BP (knowldge Base) and here in the forum how to use it.
regards
Silvio

[wxlwinner]

Hi Silvio,thanks a lot for your help, I will try it.