It looks like its limiting your data to the contacts connected to accounts via your Account Linkage.
You might need to check the linkage field on the 250 which dont appear.
If they're not linked I'd suggest creating a program canvas to default contacts without an account to a NULL account value linking them to a NULL dummy account.
That way they will appear in the report and you can easily manage your unmatched contacts with a report on the NULL account.
Hi John Alexander,
Thanks for the response.
Seems its not a linkage issue because all the 750 records are displayed in Classic Insight but not in New Insight.