Unauthorized when trying to to connect to NS8 for migration

Can you ping the wireguard IP of NS8 from the NS7?

To check the wireguard connection on NS8 or NS7 you could use the wg command.

On the NS8, do you get more entries than one?

redis-cli keys node/*/vpn

There was a bug but it should already be fixed. Maybe you need to adapt the WG IPs manually.