PO PDF cannot be viewed online and attached from Email for requester

Hi Everyone,

We have created custom data model for PO PDF.

We checked that the error caused for the PO PDF cannot sent to our requester after PO created.

Is there any advice with using custom PO data model?

We also grant the access follow the instruction of

PRC:PO: BPM/Email Error - An Error Occurred While Copying Document Attachments To This Notification (Doc ID 2547764.1)

But it still cannot work.

For standard data model used, the PO PDF can send into our requester through Email.

For custom data model used, the email showed with below error in header without PO attachment.