Delay before downloading email after installing NIS 2013

I have just moved over from AVG to NIS 2013 and am finding that, when I click to send/receive mail in Outlook, the send happens immediately as before but there is a fairly long delay before the download of received mail starts. I am not using the mail scanning at all since my ISP covers me for most things. Is there something else I need to do to get rid of this delay, please?

 

Cheers,

 

Joan