Hi Mamoun Abuagla,
The upgrade to 1.2.1 should have maintained the customised IP address that was previous configured into that V1000. Can you try using that? If it’s unknown, try entering the recovery webpage; the configured system IP address is printed on the 1.2.1 recovery page.
You can also use link local IPv6 IPaddress - this IP address will never be changed and you can figure it out by using the MAC address of the radio. use any tool from internet (e.g. MAC address to IPv6 link-local address online converter – Ben's blog) to calculate Link Local IPv6 IP address. then use this link to login: https://[Ipv6-address]