Thank you @mrmarkuz. Please find related answers below.
[root@neth ~]# yum list nethserver-ns8-migration nethserver-ns8-migration.x86_64 1.3.4-1.ns7 @nethserver-updatesnethserver-updates
Installed Packages
nethserver-ns8-migration.x86_64 1.3.4-1.ns7
Did you change the default 10.5.4.0/24 wireguard network?
No
Does pinging 10.0.1.1 still work from the NS7?
yes
For aborting a migration of an app manually see NS7 to NS8 Migration issue - #11 by davidep
If nothing works you can reset the migration on NS7 so the NS7 services are working again and you can start over with a fresh NS8, see GitHub - NethServer/nethserver-ns8-migration
Ok, got it. But would try to avoid it because resyncing needs several days to huge amount of data.
I think this is something different. Ping is still working and no firewall in between.