2417771 - PR details not displayed in My inbox app due to error 500

This KBA applies to the following symptoms:

• oData Service C_PURREQUISITIONITEM_FS_SRV is failing with error '500 Internal server error'.
     
• Purchase requisition details are not displayed in My Inbox app.
     
• When trying to display a PR in My Inbox app, the following error is shown: "Could not display data. Contact your system administrator".
     
• In ST22, we can see the following dump:
  Category               ABAP programming error
  Runtime Errors         GETWA_NOT_ASSIGNED
  ABAP Program           CL_C_PURREQUISITIONITE_DPC_EXTCP
  Application Component  MM-PUR-REQ

• Materials Management (MM)
• SAP S/4HANA, on-premise edition 1511
• SAP S/4HANA 1610
• SAP S/4HANA 2020

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