Your description is somewhat unclear and could mean several possible scenarios. What is the exact error message you see? That is a key indicator of a solution. Being locked out of an account is one possible indicator you do not
know the password after all.
"If you forgot the answers to your Apple ID security questions" click here --> https://support.apple.com/HT201485
If you see the message "not sufficient information" see if at this stage you can still sign up for Two Factor Authentication:
Two-factor authentication for Apple ID --> https://support.apple.com/HT204915
If you cannot resolve the issue by signing up for Two Factor Authentication, "Contact Apple for help with Apple ID account security"; click here --> https://support.apple.com/HT204169