Robert Harris appeals pro se the dismissal of his second motion to vacate. 28 *737 U.S.C. § 2255. The district court dismissed Harris’s motion for failure to obtain leave to file a second or successive motion. 28 U.S.C. §§ 2244(b)(3)(A), 2255(h). We affirm.

Harris has waived any challenge that he could have made to the dismissal of his second motion to vacate. The district court “[dismissed [Harris’s motion] as successive” and instructed him to “petition the Eleventh Circuit for permission to file a successive motion.” But Harris disregarded his obligation to file “the appropriate form provided by the clerk of this court” to request leave to file a successive motion. See 11th Cir. R. 22-3(a); Moton v. Cowart, 631 F.3d 1337, 1340 n.2 (11th Cir. 2011) (requiring pro se litigants “to conform to procedural rules”). The district court was required to dismiss Harris’s motion sua sponte because, “[without authorization, the district court lacks jurisdiction to consider a second or successive [motion].” United States v. Holt, 417 F.3d 1172, 1175 (11th Cir. 2005). Because Harris does not dispute that his motion is barred as successive, we deem abandoned any challenge that he could have made to the dismissal of his motion. See Timson v. Sampson, 518 F.3d 870, 874 (11th Cir. 2008). Harris argues in his reply brief for “this Court [to] liberally construe [his] [initial] brief as an implied petition to file a second or successive ... motion,” but our precedent holds that “we do not address arguments raised for the first time in a pro se litigant’s reply brief,” id.

We AFFIRM the dismissal of Harris’s second motion to vacate.