When authorized by section 76-1442, service of a summons issued under such section may be made by posting a copy on the front door of the dwelling unit and mailing a copy by first-class mail to the defendant's last-known address. The plaintiff shall file an affidavit with the court describing the diligent efforts made to serve the summons in the manner provided in sections 25-505.01 to 25-516.01, the reasons why such service was unsuccessful, and that service was made by posting the summons on the front door of the dwelling unit and mailing a copy by first-class mail to the defendant's last-known address.