@hobhob
It could be due to some scripts you have installed, upgrade to latest version to overwrite files.
Had the same issue, upgrading kinda fixed the issue.
Type your comment> @CyberPanel said:
> The wp-config.php in the child domain is the same as the master config?
>
> No, wp-config.php in child-domain is not same, new database is created and dump of master site is restored in child-do…