Sophos UTM 320 , reset all passwords

hello

we have Sophos utm with OS utm  version 9.6 , we forgot all passwords.

we follow : https://support.sophos.com/support/s/article/KB-000034260?language=en_US , all steps are done successfully>

but when access webadmin (admin,admin)  doesn't ask me for new password after that, it still give me invalid user or password.

any ideas ?

and we apply another thread suggestion to apply cc passwd ClosedDoor, but it gives error : "can't use string ("0") as a hash ref while "strict refs " in use at confd-client.pl" "

Note :

1- we are using monitor and usb keyboard

2- we don't know the webadmin user name (admin or has changed before), but (cc get_user_by_name admin   returns 0)

thanks a lot