NS7 -> NS8 mail migration error


we would like to migrate NS7 mail to NS8. but there was an error right after Migration starting.
In the logs we find this:

2024-06-09T08:13:35+02:00 [1:mail1:agent@mail1] task/module/mail1/302c2a85-afdf-4399-849b-695508a3aa61: configure-module/90mail_domain is starting
2024-06-09T08:13:36+02:00 [1:mail1:dovecot] doveadm( Executing command ‘mailbox create’ as ‘vmail’
2024-06-09T08:13:36+02:00 [1:mail1:dovecot] doveadm(vmail)<85>: Error: mkdir(/var/lib/vmail/vmail/Maildir) failed: Permission denied (euid=100(vmail) egid=101(vmail) missing +w perm: /var/lib/vmail, dir owned by 0:0 mode=0755)
2024-06-09T08:13:36+02:00 [1:mail1:dovecot] doveadm(vmail)<85>: Error: Can’t create mailbox postmaster: Internal error occurred. Refer to server log for more information. [2024-06-09 06:13:36]
2024-06-09T08:13:36+02:00 [1:mail1:dovecot] doveadm(85): Error: Command mailbox create failed
2024-06-09T08:13:36+02:00 [1:mail1:dovecot] doveadm(85): doveadm: - - “POST /doveadm/v1 HTTP/1.1” 200 109 “” “python-requests/2.31.0”
2024-06-09T08:13:36+02:00 [1:mail1:agent@mail1] Traceback (most recent call last):
2024-06-09T08:13:36+02:00 [1:mail1:agent@mail1] File “/home/mail1/.config/actions/configure-module/90mail_domain”, line 32, in
2024-06-09T08:13:36+02:00 [1:mail1:agent@mail1] mail.doveadm_query(“mailboxCreate”, {“mailbox”: [“postmaster”], “user”: “vmail”})
2024-06-09T08:13:36+02:00 [1:mail1:agent@mail1] File “/home/mail1/.config/pypkg/mail.py”, line 273, in doveadm_query
2024-06-09T08:13:36+02:00 [1:mail1:agent@mail1] mail.DoveadmError: [[‘error’, {‘type’: ‘exitCode’, ‘exitCode’: 75}, ‘mailboxCreate’]]

To solve the problem, we ran this on NS8 server:
#runagent -m mail1 podman exec -ti dovecot bash
#chown vmail:vmail /var/lib/vmail
#chmod 700 /var/lib/vmail

The /var/lib/vmail was root:root owned with 755 rights.
It seems the mail1 module is running now and but the data sync is failed without any error.
We tried to abort the migration, it failed, we have to manually delete the mail module/app. There were files on NS7 in /var/lib/nethserver/migration/mail (?, i dont’t remember exactly) what we have to delete, to restart the mail migration,
but if the mail module is installed by migrator, this file rights problem always caueses error. If we install the mail module manually, there is no error, but the migrator do not use the existing mail module, it always create a new mail module.

Can someone fix the problem?