If the transaction is not submitted by the person who made the purchase, the transaction cannot be exported. The person who made the transaction or Admin then needs to submit the transaction in order for it to be exported.
In order to submit a transaction, you need to select the category of the transaction.
Have you selected a category but still can't submit the transaction?
If you have settings on category level that makes "participants" and "vat" for example, as mandatory for this category, those field will be red and needs to be filled out.
Go to "accounting settings" and "categories" to change this setting in the category.
Is the transaction reserved?
The transaction may also be reserved and not yet completed, in which case it is not possible to export the transaction. Wait until the yellow clock symbol disappears to export the transaction.