Ordered that the order is affirmed, with costs.
The Supreme Court properly denied the plaintiffs motion to vacate a prior order of the same court entered upon her default in opposing the respondent's motion pursuant to CPLR 1021, inter alia, to dismiss the action for failure to timely substitute a representative. To be relieved of her default in opposing the respondent's motion, the plaintiff was required to show a reasonable excuse for the default and a meritorious cause of action ( see Nowell v NYU Med. Ctr., 55 AD3d 573, 574; Raciti v Sands Point Nursing Home, 54 AD3d 1014; Simpson v Tommy Hilftger U.S.A., Inc., 48 AD3d 389, 392; Bauer v Mars Assoc., 35 AD3d 333). The excuse of law office failure was vague and unsubstantiated and, thus, did not constitute a reasonable excuse for the default ( see Chechen v Spencer, 68 AD3d 801; Murray v New York City Health Hosps. Corp., 52 AD3d 792, 793; St. Luke's Roosevelt Hosp. v Blue Ridge Ins. Co., 21 AD3d 946, 947). Furthermore, the plaintiff failed to demonstrate that the action had merit ( see Mosberg v Elahi, 80 NY2d 941, 942; Salch v Paratore, 60 NY2d 851, 852; Murray v New York City Health Hosps. Corp., 52 AD3d at 794; Bauer v Mars Assoc., 35 AD3d at 334; McDonnell v Draizin, 24 AD3d 628, 629).
The plaintiffs contention that she did not default in opposing the respondent's motion is improperly raised for the first time on appeal ( see Pugliese v Mondello, 67 AD3d 880; Fletcher v Westbury Toyota, Inc., 67 AD3d 730; Matter of West Bushwick Urban Renewal Area Phase, 2 69 AD3d 176; Freitas v City of New York, 66 AD3d 732).