The Third Department, reversing Supreme Court, determined the default judgment was a nullity because the process server did not timely file the affidavit of service. The defect is not jurisdictional and can be cured. But the default judgment cannot be reinstated retroactively. Once properly served the defendant may submit an answer:
… [P]laintiff’s process server effectuated service by delivery and mail (see CPLR 308 ) on November 17, 2017. Plaintiff’s proof of service, however, was not filed with the clerk of the court until December 11, 2017, more than 20 days after the delivery and mailing. Accordingly, the filing was untimely and, as such, service of process was never completed (see CPLR 308  …).
… [F]ailure to timely file proof of service is only a procedural irregularity, as opposed to a jurisdictional defect, and a court may, sua sponte, issue an order curing said irregularity (see CPLR 2001, 2004 … ). “A court may not, however, make that relief retroactive to a defendant’s prejudice by placing the defendant in default as of a date prior to the order, nor may a court give effect to a default judgment that, prior to the curing of the irregularity, was a nullity requiring vacatur” … . Here, no such curative order was ever sought from or issued by Supreme Court and, therefore, defendant’s time to answer never began to run such that the resulting default judgment was a nullity requiring vacatur … . Miller Greenberg Mgt. Group, LLC v Couture, 2021 NY Slip Op 02566, Third Dept 4-29-21