[Wolves] Why isn't mail arriving - exim/dovecot

[Wayne Morris]

Hi,
I have an alias to my main email address - which has correctly diverted 
mail arriving at 'training' to my address.
Decided to create a new user name with useradd, and have its own mailbox.
Now mail for training is on the system in /var/spool/mail/training
but trying to collect it using imap thunderbird  - nothing shown.

Any ideas?

thanks