Ancestry DNA matching

[MuzzaKiwi]

Hi I’ve done my ancestry DNA, and I’m looking to see if any body has matched back to Captain John Grono and his wife Elizabeth Bristow of NSW dying in the 1840s Ebenezer. They had a large family. I believe I’m from there daughter Jane Grono whom married (2) Michael Mitchell. My current DNA shows no known DNA connection to Grono, but Iam to the Mitchell family all be it one son. Curious to know who is linked and why this doesn’t show on my thru lines
Cheers
Murray