As described here https://dev.gnupg.org/T6683#176429 the displayed information here may be misleading:
{F5259025}
This is seen (after a explaining/warning window) when sending a signed mail with "prefer S/MIME" but no S/MIME certificate.
Confusing are:
a) the text "Identität und Integrität nicht bestätigen" ("Don't confirm identity and integrity")
b) the "VS-NfD compliant" in the bottom left corner (I know it is supposed to mean that the installation is compliant, but...)
c) the green OK button
For a)
* Ingo suggested "Don't confirm identity and integrity of the email"
* My idea would be to add to that "/ Don't sign the email". Which might be a bit long, I admit...
For c) I suggest either a (functioning) red button or one without color and without shield icon