Locked out from my icloud account

Question

I had apple id and was using the same to access icloud account. Few months back I changed primary e mail address and my previous apple id email login was set in the email adresses of account. Now after installing new operating system it is not accepting new apple id e mail and asking for password of previous appleid. Please advise if anyone knows what can be done

Answer 1

Here ya go:
Rescue email address
A rescue address helps secure your Apple ID account against unauthorized access by someone who gains control of your primary address. If you have a rescue address, it receives all security-related Apple ID email instead of your primary address, including the email needed to reset your password or security questions.
Go to My Apple ID (appleid.apple.com).
Select “Manage your Apple ID” and sign in.
Select “Password and Security” on the left side of the page. You may be asked to answer one or more security questions before continuing. Forgot the answers?
If you see a list of three security questions, your account has the option to use a rescue address.
Accounts that have fewer than three questions don't have and don't need a rescue address.
Accounts that use two-step verification don't have and don't need a rescue address or security questions.
Add a rescue address:
Select Add Email Address, then enter your rescue address. Apple will send a verification email to that address. Didn't receive the email?
Follow the instructions in the email to verify the address. If you don't verify the address, security-related email continues to go to your primary address.
Edit a rescue address:
Select Edit next to the address, then enter the new address. Apple will send a verification email to that address. Didn't receive the email?
Follow the instructions in the email to verify the address. If you don't verify the address, security-related email continues to go to your primary address.
Delete a rescue address: Select Delete next to the address.
Cheers,
GB