Hi,

Looks like you are on a cPanel installation (Exim is cPanel's default choice).
Even i had a similar thing. Check if the domains that are failing are listed in /etc/localdomains but still not on your new server and also check the /etc/valiases

I believe it's more to do with Server Setup. Beyond this you could contact Support of your service provider...

try /usr/sbin/sendmail -t -v
if that's the path to sendmail wrapper alongwith what has been suggested earlier in thread.

Anup