physical forwarding prohibited; PD PR
Computing term used in email or messaging systems to indicate that a message must not be forwarded to another physical address or device. The abbreviation 'PD PR' is an English-derived shorthand.
This email has the 'physical forwarding prohibited' flag set.
物理的回送禁止の設定を確認してください。
Please check the physical forwarding prohibited setting.
Compound of 物理的 (physical) + 回送 (forwarding) + 禁止 (prohibition). A technical term likely coined in Japanese computing contexts.