PlanManager allows you to export your invoices to your accounting software.
Internally, PlanManager keeps track of which invoices have already been exported to avoid accidentally exporting 2x the same invoice. When the import is unsuccessful in your accounting software and you want to resend the invoices, you can ask PlanManager to reconvert invoices for export.
To turn invoices ready again, go to Invoicing - Accounting ① & ②. Indicate what invoices you want to re-set, by filtering date or invoice numbers ③ & ④. Then click the reset invoices button ⑤. You Will now be able to export them once again.