A family of Microsoft relational database management systems designed for ease of use.
Unfortunately, Access doesn't support CTEs. That would be handy.
Because using Format() on dates converts the result from a date value to a string value, you have to be careful how you do that, as Erland pointed out.
There are probably 3 or 4 ways to get the result you want in Access.
I might do it this way. Or you could try a different order by that doesn't rely on formatting the date.
SELECT Format([YourDateFieldGoesHere], "mm-dd-yyyy") AS DOS,
COUNT(*) AS DailyCount
FROM tblYourTableNameGoesHere
GROUP BY Format([YourDateFieldGoesHere], "mm-dd-yyyy"),
Format(tblIndividual.Birthdate, "YYYYmmdd")
ORDER BY Format(tblIndividual.Birthdate, "YYYYmmdd") DESC;