AHRI Certificates can be found on the AHRI directory website.
https://www.ahridirectory.org/Search/SearchHome
For Large Products covered under AHRI 340/360
From AHRI Home Directory Tab -> Product Type -> Commercial -> Unitary Large Equipment -> AHRI Rating Conditions -> Brand Name -> AAON
https://www.ahridirectory.org/NewSearch?programId=3&searchTypeId=3&productTypeId=3401
For Small Products covered under AHRI 210/240
From AHRI Home Directory Tab -> Product Type -> Residential -> Air Conditioners and Air Conditioner Coils -> AHRI Rating Conditions -> Brand Name -> AAON
From this location you can search for Manufacturer “AAON”. You can also search by Model Number to narrow down the results or the exact model, voltage, and cooling option you are looking for Example (RN-015-3-*-EB).