how to reset security questions

How to reset security questions ? I know the password and login for my account. I was able to log into icloud, it determined my name and what iPhone I have, but I can’t log into my account because it asks me to answer security questions, the answers to which I registered 15 years ago and forgot them. All the time he writes insufficient information to confirm his identity and reset the answers to these questions. I never had a backup email, and at that time no one warned me that I would need it. Iphone 4s cannot even contact the apple id servers, although the Internet is working and the pages are loading.