Summary
The orders report system currently cannot build a file from promotion filters that contain double spaces in their names, when trying to build the report the system generates an error and the export is not performed, resulting in the message "Export completed. 0 orders were sent to your email".
Simulation
Create order using some promotion whose name contains double spaces;
After that, go into order management and run a filter with this promotion as condition.
At this point, the OMS UI will normally display a list of orders with the chosen condition, but when selecting export orders the UI will return the following message "Export completed. 0 orders have been sent to your email".
Workaround
Filter the orders in the UI by another parameter e.g. date, payment method etc., then export the orders and filter them by promotion directly in the Excel file generated by the system.