Once you've fixed the issues that were preventing documents from being made in QuickBooks Online, then you can retry the import.
Click on "Batch actions" and retry import for the items you've selected or Retry Import For All items.
You can filter out all the failed orders below and then try the batch retry import option.
On any page, you can bring up the search and filter options. Filter by Import Failed to see all transactions that have not been imported.