Fields in pdf-preview are empty (Outlook & Apple Mail)

[GitCybers]

Hello,
the fields in the generated pfd-file are empty in the pdf-preview of my email client. But if I download the attached pdf-file the formular-fileds are filled out. The file in /fileadmin/powermailpdf is also filled out correctly. Why can't I see the filled out fields in the pdf-preview of my mail client?
I published the pdf-formular with openoffice. This is my konfiguration in the constants and in the setup:
plugin.tx_powermailpdf.settings.enablePowermailPdf = 1 plugin.tx_powermailpdf.settings.fillPdf = 1 plugin.tx_powermailpdf.settings.sourceFile = fileadmin/powermailpdf/Mitgliedsantrag.pdf plugin.tx_powermailpdf.settings.email.attachFile = 1 plugin.tx_powermailpdf.settings.sender.attachment = 1 plugin.tx_powermailpdf.settings.receiver.attachment = 1 plugin.tx_powermailpdf.settings.filelink { jumpurl = 1 jumpurl.secure = 1 jumpurl.secure.mimeTypes = pdf=application/pdf icon = 1 icon_link = 1 } plugin.tx_powermailpdf.settings.fieldMap{ #pdfField = PowermailField PDFVorname = vorname PDFNachname = nachname PDFKind = schulkinder PDFKlasse = aktuelleklasse PDFBetrag = mitgliedsbeitrag PDFBetrag1 = mitgliedsbeitrag PDFStrasse = strassehausnummer PDFOrt = ort PDFPostleitzahl = postleitzahl PDFEmailadresse = email_adresse PDFKontoinhaber = kontoinhaber PDFIBAN = iban PDFBankname = namederbank } target{ cat=plugin.tx_powermailpdf/settings; type=string; label=Target pdf:Format StoragePid:Folder pdf = 1:powermailpdf }