To perform whitelisting in Proofpoint, please follow the official Safelisting Addresses guide.
For the necessary whitelisting information, please refer to the SoSafe Manager under Dispatch > Whitelisting. Depending on the booked package, you can also get this information from the following link: https://manager.sosafe.de/?redirect=whtlstng.
If you are using the Targeted Attack Protection, please also check: Proofpoint TAP (Targeted Attack Protection)