This property specifies the number of failed deliveries can occur before the mailer stops attempting delivery. (NDR is an acronym for Non-Delivered-Response )
IDL Definition
[propget]
HRESULT NDRThreshold([out, retval] VARIANT *pVal /*VT_I4*/);
[propput]
HRESULT NDRThreshold([in] long newVal);
Type
LONG
Default
3