Internet disconnects after a period of time

Hi All,

Wondering if someone can help me - I have a Fortiguard 100E NGFW deployed in an enterprise network which uses AD user groups to authenticate users out to the internet.  Now, i have a situation where a new app is installed on a server which polls some data to the Internet - however the FW "times out" the user account after a period of time.

Contacted Fortinet support and the maximum time i can set that to is 24hrs - which is not much use as the server pretty much sits dormant most of the times.  is there a way to circumvent this so the server doesnt get the same policies applied or a different method which would allow the server to stay connected to the internet without having to re-autehnticate??

apologies im not the best with firewalls so just after basic advise please.