Initialisation warn all disk will be deleted

[vai0l0]

in the process of updating to TOS5
after reboot the nas is reported as uninitialised see pic

after selecting a custom initialisation a warning appears that data on hard drives will be deleted. see pic

Nas F5-421
initially installed on a single disk (right slot)
then 4 more disks where added in raid 5 configuration

any suggestion?

[vai0l0]

ssh on port 9222 failed with incorrect password

[vai0l0]

followed https://player.vimeo.com/video/371314950?
and booted with no disk, inserted when requested and upgrade process went on smoothly