Listsource not yielding results - direct mail

[John Dreher]

Hi everybody. Has anybody had this issue with Listsource?  I tried to pull a high equity list and yielded zero results. Then deleted all of the criteria except for just one zip code and it yielded only 37 results.  This is a very densely populated area. Are there areas that Listsource doesn’t get data, or could I be doing something wrong?  Thanks for any help.