The ability to change your email address via your profile was removed several years ago. The only way to do it is to contact the Editor and request the change...
Why bother, really. I changed my email address over a year ago, and I can still post. If I do ask a question I don't miss all those emails telling me I have an answer......I can see that for myself.
I did contact the ed a few weeks ago about getting mine changed and received a reply telling me the only way the could (would!) do it was by deleting my account totally including all answers I'd ever given so I could re register with the same user name and start from scratch as a green user.
It works for me. I changed mine a few months ago. I've just changed mine again now and it's gone through okay. Maybe people aren't pressing the submit button at the bottom of the page