Google isn't sending me a verification code. What should I do?

Hey guys, I wanted to get into my second email address, which is purely for gaming. When I enter the password, it loads for 2-3 seconds and then a box appears saying that a confirmation code has been sent to the specified email address. However, the email is my main email address; there's no confirmation code in any of my inboxes or spam folders, and the phone number stored in my account is my old one, which I unfortunately no longer have access to. Does anyone know why I'm not getting a code or what I can do about it?
thanks in advance