Subscribe Pro has the ability to send an Upcoming Subscription Order email to your customers, notifying them that their next order will ship soon. There are a number of configuration settings which control the scheduling of this email. To ensure the Upcoming Subscription Order transactional email is scheduled for your customers' subscriptions, check the following configuration settings.
Under System > Configuration > Ordering Settings ensure that Automatic Ordering setting is Enabled.
Ensure that Upcoming Subscription Order transactional email is NOT Disabled. Under System > Configuration > Email Settings, make sure the box next to
upcoming_subscription_orderis not checked.
Set the number of days ahead of the upcoming order date which the email notification should be sent to your customer. Under System > Configuration > Email Settings, set the Send Email n Days Ahead of Order setting. The default value is 2 days.
Set the time of day for sending Upcoming Order emails. Under System > Configuration > Email Settings, set the Send Email At time setting to the correct time of day. NOTE: This setting is set in UTC time.