I changed my Stack Overflow account email under profile/email settings and verified my new email address from my email account. However, I am unable to sign in with the new email. The old email still works for login. When I signed out, I couldn’t sign in again with the new email.
Changing my email account and verifying it, I should be able to login with it.
You did it in the wrong place.
To add another way to login, go to the "My Logins" page, and in there click "Add more logins" button.
Then in the next screen you can add another email and a password with which you will be able to login.
Note that it doesn't remove the previous email used for login, you'll have to remove it manually in the My Logins page if you don't want to use it anymore.
That's because The email address is associated with your account but no password is associated with it yet, so it can’t be used to log in.
To be able to login with the new email, you have to click "forgot password" and follow the link that will be sent to your email to set a new password for the email and try signing again.
