How to access my old icloud photos when I forgot my old iphone passcode which is broken but when I do know my icloud user name and password

My new iphone cant access old icloud photos since I dont remember old iphone passcode. But I do remember my icloud credentials and I am using the same apple account in my new phone which used in old phone as well. But the system asking me the old iphone password to restore my old photos. Any idea how to access my old photos?