Serving someone with only their DL# and DOB

What is the name of your state (only U.S. law)? California

Hello All

Im in ther process of serving someone but in order to do so I need to have an address. I only have their driver license number and date of birth to go off. I was told that I need to hire a private investigator to find thier address in order for them to be served. Is this true? Can someone help?

Well what address did you put on the claim and why isn't THAT address good enough?