postfix problem after migration

I can see email from within virtualmin but when try to check it with outlook show nothig. I do not get error from outlook. login successful but nothing downloaded.
from another linux server I do:

openssl s_client -connect
+OK Dovecot ready.
user user.domain
pass password
+OK Logged in.
+OK 0 messages:

why do not show my emails!??

You mention having done a migration. Is the DNS for pointing at the correct place?