If you are unable to serve him any other way, you can file a motion for substituted service. You will need proof of your attempts to serve him.OK, now I'm back to question on post #70. If I ask his county sheriff's department, or hire a private process server, I still have the address I cannot be positive that he lives at. Is it like, I tried both options, if no result, I request for "motion for substituted service"? Which is to leave the notice on the door of his residence? What if that fails as well?
You might want a private investigator to locate a valid address.