MEMORANDUM **

Winston Bontrager and Pauline Anderson (“Defendants”) appeal their con *666 victions stemming from a tax-evasion scheme. We affirm.

We review Defendants’ prosecutorial misconduct claims for plain error because no objection was made below. See United States v. Tomsha-Miguel, 766 F.3d 1041, 1047 (9th Cir. 2014). It is clear that some misconduct occurred. For example, it was improper for the prosecutor to refer to Bontrager’s accountant, a prosecution witness, as “meticulous, careful and honest,” when the accountant offered strong evidence against Bontrager. See United States v. Necoechea, 986 F.2d 1273, 1276 (9th Cir. 1993) (“Vouching consists of placing the prestige of the government behind a witness through personal assurances of the witness’s veracity, or suggesting that information not presented to the jury supports the witness’s testimony.”); United States v. Kerr, 981 F.2d 1050, 1053 (9th Cir. 1992) (holding that it was impermissible vouching for prosecutor to say in closing argument that a prosecution witness “was candid. I think he was honest”). It also was improper for the prosecutor to offer his own account of when federal agents “spring into action” and “careful[ly] ... [and] methodically].... go through every piece of evidence” in preparing a case for trial, an account that had no basis in the evidence. Cf. United States v. Alcantara-Castillo, 788 F.3d 1186, 1195-96 (9th Cir. 2015).

Furthermore, although Defendants’ lavish spending was indisputably relevant to the tax charges, see United States v. Johnson, 319 U.S. 503, 517, 63 S.Ct. 1233, 87 L.Ed. 1546 (1943), the prosecution repeatedly crossed the line with comments such as those asserting that Defendants “lived a life that most of us can only dream of.” Finally, it was improper when, notwithstanding a jury instruction to the contrary, both defense counsel and the prosecution discussed the testimony of Bontrager’s ex-girlfriend in relation to Anderson’s guilt or innocence.

We affirm, however, because Defendants have failed to establish that any of the alleged misconduct “affected the outcome of the district court proceedings.” United States v. Chi Mak, 683 F.3d 1126, 1133 (9th Cir. 2012) (quoting Puckett v. United States, 556 U.S. 129, 135, 129 S.Ct. 1423, 173 L.Ed.2d 266 (2009)). This was not a close case. The evidence of guilt was overwhelming and Defendants have failed to show that the credibility of the vouched-for witnesses was meaningfully challenged. See United States v. Weather-spoon, 410 F.3d 1142, 1151 (9th Cir. 2005) (“When the case [against a defendant] is particularly strong, the likelihood that prosecutorial misconduct will affect the defendant’s substantial rights is lessened because the jury’s deliberations are less apt to be influenced.”). Nonetheless, in light of the numerous, obvious instances of im-. proper argument by the prosecutor, particularly improper vouching, we are disturbed that the government refused to concede any error in its briefing or at oral argument, despite repeated invitations to do so by the panel. See Berger v. United States, 295 U.S. 78, 88, 55 S.Ct. 629, 79 L.Ed. 1314 (1935) (“[W]hile [a prosecutor] may strike hard blows, he is not at liberty to strike foul ones.”).

Anderson’s challenge to the voir dire questions also does not warrant reversal. The prosecutor’s questions did not bias the jury against Defendants and were not “so unreasonable [that allowing them] constitute[d] an abuse of discretion.” United States v. Anzalone, 886 F.2d 229, 234 (9th Cir. 1989) (quoting United States v. Flores-Elias, 650 F.2d 1149, 1151 (9th Cir. 1981)).

The district court did not err when it admitted evidence of Bontrager’s prior conviction pursuant to Federal Rule of Evidence 404(b). See Huddleston v. United *667 States, 485 U.S. 681, 685-86, 108 S.Ct. 1496, 99 L.Ed.2d 771 (1988); United States v. Marashi, 913 F.2d 724, 734-35 (9th Cir. 1990); Fed.R.Evid. 403. Contrary to Defendants’ contention, the trial evidence regarding the prior conviction was consistent with the prosecution’s pre-trial proffer. 1

Finally, in light of the strength of the prosecution’s case, reversal is also not warranted under the cumulative error doctrine. See United States v. Fernandez, 388 F.3d 1199, 1256-57 (9th Cir. 2004), amended in non-relevant part, 425 F.3d 1248 (9th Cir. 2005).

AFFIRMED.