| Platform SDK: Exchange Server |
The X.400 standard specifies that the properties PR_NDR_DIAG_CODE and PR_NDR_REASON_CODE should always occur together, but MAPI can generate nondelivery reports which contain only PR_NDR_DIAG_CODE. Therefore, these two properties are not always paired in Microsoft Exchange Server reports.
The values for PR_NDR_DIAG_CODE are listed in MAPITAGS.H, which is part of the MAPI SDK. Its default value is MAPI_DIAG_NO_DIAGNOSTIC.
The values for PR_NDR_REASON_CODE are also listed in MAPITAGS.H. Its default value is MAPI_REASON_TRANSFER_FAILED.