By default, Satago will synchronise with your accounting system once a night.
This means if you do your reconciliations in your accounting software during the day, the reminders that are sent the following day will reflect the current status of all your invoices. i.e. we will not send reminders for invoices that you have marked as paid.
You can force Satago to do an immediate update by navigating to Admin > Organisation > Options, and clicking on the Import Now button next to your accounting system.
If you are using a desktop-hosted accounts package, remember to run your Satago connector first!