Which method is NOT considered valid for service after initial service?

Using unsolicited electronic mail is not considered a valid method for service after initial service because legal procedures require methods that can ensure receipt and a definitive record of service. Traditional methods of service, such as handing the document to the person, leaving it at their office or dwelling, and sending it via postal service, all provide a structured approach to ensure that the individual receives the documents and can acknowledge them appropriately.

Unsolicited electronic mail does not have the same legal standing, as it lacks the necessary reliability and documentation associated with recognized methods of service. Recipients may disregard or not receive unsolicited emails, making it difficult to prove that service was effectively completed. Legal processes typically require a confirmed acknowledgment of receipt, which is not guaranteed through such informal and unregulated means as unsolicited electronic communications.