This query was working fine, but then all of a sudden it stopped pulling data. No errors, just empty results.

SELECT Salutation.Salutation, Valid_Numbers.[First Name], Valid_Numbers.[Last Name], Valid_Numbers.[House Number] & " " & [Street Name] AS Address, Valid_Numbers.City, Valid_Numbers.ST, Valid_Numbers.ZIP, Valid_Numbers.[Date of Birth]
FROM Salutation INNER JOIN Valid_Numbers ON Salutation.ID=Valid_Numbers.Salutation
WHERE switch(Len([date of birth])=7,Left([date of birth],2)=Month(Date()),Len([date of birth])=6,left([date of birth],1)=Month(Date()));