Out of State Affidavit: CPLR § 2309(c); RPL § 299-a (1) Substance Rules the Day

CPLR § 2309 Oaths and affirmations
(c) Oaths and affirmations taken without the state.

RPL § 299-a. Acknowledgment to conform to law of New York or of place where taken; certificate of conformity

Andromeda Med. Care, P.C. v Utica Mut. Ins. Co., 2009 NY Slip Op 51629(U) (App. Term, 2nd, 2009)

The affidavits proffered by defendant in support of its
motion for summary judgment were executed out of state. Although the
affidavits were accompanied by documents that purported to be
certificates of conformity, the certificates did not comply with Real
Property Law § 299-a and, thus, the affidavits did not comply with CPLR
2309 (c) (see Ford Motor Credit Co. v Prestige Gown Cleaning Serv.,
193 Misc 2d 262 [2002])
. Since this defect was duly objected to by
plaintiff in the Civil Court, defendant failed to introduce competent
evidence in admissible form establishing its entitlement to summary
judgment (see Impulse Chiropractic, P.C. v New York Cent. Mut. Fire Ins. Co., 19 Misc 3d 127[A],
2008 NY Slip Op 50498[U] [App Term, 2d & 11th Jud Dists 2008]).
Consequently, defendant's motion for summary judgment should have been
denied (id.).

This issue seem peculiar to no-fault litigation.  While you see it pop up here in there in other areas of law, it is not nearly as frequent as it is in no-fault.