Appleid- changing secondary email to primary - won't verify?

My apple id has 2 emails listed, a primary and a secondary one. I want to change it so the primary one is the one that is currently the secondary. I've tried 2 ways of doing this, neither have worked. Both current email addresses are verified. First, delete the secondary address, and then enter that email as the primary one - I get the verification email sent, resend button, but no email ever arrives (it's a gmail account) no matter how many times I press resend. Even though the email address is already verified. Second method, don't delete the secondary secondary address, just change the primary one to the same (gmail account still) - get the same result, verification email sent, resend. No email arrives, no green checkmark appears. Any ideas?