When sharing a PDF file, the error occurs: [ShareSheet] connection invalidated

I tried the share method with the URL link in my bundle and the PDF can also be shared. But as soon as I try to share my saved (core data with reference to documentDirectory where the PDF's are located) the error [ShareSheet] connection invalidated.

Is it because the PDFs are saved as a set? Because I can't show the set as a url either because the share method works with a url?

class ViewController: UIViewController {
    
    //In my code I have this var from my core data entity
    var pdfAdresse: PDFAdresse!

    //If you press a collection view item for a long time, I create the following method
    @objc func longPressPDF(_ sender: UIGestureRecognizer) {
        if sender.state == UIGestureRecognizer.State.ended {
            let longPressLocationPoint = sender.location(in: self.collectionView)
                
            if let pressIndexPath = self.collectionView.indexPathForItem(at: longPressLocationPoint) {
                print("\(pressIndexPath)")
                
                let alertController = UIAlertController(title: "Menü", message: "", preferredStyle: .alert)
                alertController.view.tintColor = UIColor.systemRed
                
                // CancelPDF
                let cancelAction = UIAlertAction(title: "Abbrechen", style: .cancel, handler: nil)
                
                // Delete PDF
                let deleteAction = UIAlertAction(title: "Löschen", style: .default) { (alertAction) in
                    let pdfFile = self.pdfAdresse.files[pressIndexPath.row]
                    CoreDataService.defaults.deletePDFfile(pdfFile)
                    self.collectionView.reloadData()
                }
                
                // Share PDF
                let shareAction = UIAlertAction(title: "Teilen", style: .default) { (alertAction) in
                    let activityController = UIActivityViewController(activityItems: [self.pdfAdresse.files[pressIndexPath.row] as Any], applicationActivities: nil)
                    activityController.popoverPresentationController?.sourceView = self.view
                    self.present(activityController, animated: true, completion: nil)
                }
                
                alertController.addAction(cancelAction)
                alertController.addAction(deleteAction)
                alertController.addAction(shareAction)
                    
                present(alertController,animated: true, completion: nil)
            }
        }
    }
}