Auto Send/Receive doesn't always work

[fredphred]

I've gotten reports from users that the auto send/receieve
function isn't working correctly. The problem is
intermittent and doesn't always show up.

The symptoms are they manually click send/receive and get
emails that are 20 mins old (from internal users) even
when their auto send/receive is set at 1 minute.

We've set the autocheck lower and it has helped some
but has not eliminated the problem.

Thanks.