Can't get Email module working.

Hi,

I'm a new user of servicedesk plus.
it looks like a great tool, but i'm struggling to get the email module working.

i've input all the settings correctly [i think].
outgoing messages work fine, but the system doesnt pickup incoming messages.

I'm using MS Exchange server on the same LAN - does servicedesk work with MS exchange?

I left the incoming mail setting set to POP, but changed the port to 25.
all authentication info is correct, but when i click the 'start fetching' button under Admin i get:
FAILURE :Email Settings saved successfully. But error occured while trying to check connection with mail server - Problem connecting to mailbox.

I've tried changing hostname to IP address also.

any ideas?

thanks for your help,

Dan Garner